Minesweepers

A pair of Avenger class mine-hunters homeported in Japan have been tracked sailing westward out of the Pacific Ocean in recent days. This comes as President Trump and other officials say an operation is taking shape to clear Iranian mines from the Strait of Hormuz, which will be essential to fully reopening that critical waterway. The United States has also now announced a blockade of all of Iran’s ports.

Until last year, the Navy had four Avenger class ships forward-deployed in the Middle East for exactly this mission. A trio of Independence class Littoral Combat Ship (LCS) configured for minesweeping duties subsequently took their place. However, those ships were redeployed from Bahrain ahead of the latest conflict with Iran, and two of them then emerged unexpectedly in Southeast Asia last month. While getting them out of the Persian Gulf was a prudent security measure, it remains unclear why the decision was made to send them literally to the other side of the globe amid the obvious threat of Iran mining the highly strategic Strait of Hormuz. One of them, the USS Tulsa, was also recently spotted sailing west after weeks in port in Singapore.

The Avenger class USS Chief and USS Pioneer were spotted arriving in Singapore on April 8, and they were seen leaving heading west on April 10. This represents half of the Avenger class ships still in Navy inventory, all of which are forward-deployed in Sasebo, Japan.

Online ship tracking site MarineTraffic subsequently showed both Avenger class ships heading northwest through the Strait of Malacca. There are unconfirmed reports that Chief and Pioneer arrived at Ao Makham port in Phuket, Thailand, earlier today. Their final destination is unknown, but USNI News had reported over the weekend that they had been “dispatched toward U.S. Central Command.”

USS Tulsa was also tracked sailing northwest in the Strait of Malacca on April 3, which we will come back to in a moment.

“U.S. Central Command (CENTCOM) forces began setting conditions for clearing mines in the Strait of Hormuz,” the command had said in a press release on April 11. The Arleigh Burke class destroyers “USS Frank E. Peterson (DDG 121) and USS Michael Murphy (DDG 112) transited the Strait of Hormuz and operated in the Arabian Gulf as part of a broader mission to ensure the strait is fully clear of sea mines previously laid by Iran’s Islamic Revolutionary Guards Corps.”

Questions have been raised about the exact purpose of sending USS Frank E. Peterson and USS Michael Murphy through the Strait, and whether either ship actually made a full transit. Michael Murphy was tracked online sailing on the Persian Gulf side, at least briefly. Neither of the destroyers are outfitted for mine clearance missions, though they do have powerful sonars that might be able to help spot mines.

“Additional U.S. forces, including underwater drones, will join the clearance effort in the coming days,” CENTCOM’s release over the weekend added, but did not further elaborate.

“We’re also bringing in more traditional minesweepers” as part of efforts to clear the Strait of Hormuz, President Trump told Fox News yesterday. He also said several times this weekend that mine-clearing operations were already underway in some form.

U.S. President Donald J. Trump said earlier that the U.S. is now in the process of clearing the Strait of Hormuz of mines, following reports that U.S. naval vessels transited the strait this morning. According to President Trump, during Operation Epic Fury, 28 Iranian mine laying… pic.twitter.com/fQGHDAmOES

— OSINTdefender (@sentdefender) April 11, 2026

CENTCOM declined to comment when we reached out today for more details about the planned force package for the mine clearance mission. TWZ has also reached out to the Navy’s main headquarters in the Pacific for more information about the movement of the Avenger class ships.

Before the latest conflict with Iran broke out in February, the Navy had three Independence class LCSs outfitted for mine countermeasures missions – Tulsa and Santa Barbara, along with the USS Canberra – forward-deployed in Bahrain. The arrival of those ships last year was tied to the long-planned decommissioning of four Avenger class vessels that had been homeported in that Middle Eastern country for decades beforehand. It is unclear how many LCSs the Navy otherwise has that are currently configured for minessweeping missions.

As noted, Tulsa and Santa Barbara subsequently emerged in Southeast Asia, first in Malaysia and then in Singapore, last month. USS Canberra‘s location remains uncertain, but it was reported to be sailing in the Indian Ocean as of March 19.

It should also be stated that the Independence class LCS is a much more modern ship than the Avenger class. When configured for the minesweeping mission, the LCSs also bring new standoff mine countermeasures capabilities, including Common Unmanned Surface Vehicle (CUSV) drone boats and helicopter-borne systems. Still, questions continue to be raised about whether the Independence class vessels are adequate replacements for the older, but purpose-built Avengers. You can read more about this here.

CUSV®

Airborne Laser Mine Detection System (ALMDS) Video

It is possible that the USS Chief and the USS Pioneer are in Southeast Asia now for exercises or other reasons. Japan-based Avenger class ships have traveled to Thailand, specifically, as well as other countries across the Pacific, to train with allied and partner forces in the past.

That being said, the movements of Chief and Pioneer in the region, as well as Tusla‘s departure from Singapore, did come right around CENTCOM’s explicit statement that more U.S. forces were heading to the Middle East to help with mine-clearing efforts. Furthermore, as already mentioned, the quartet of Avenger class ships in Japan, as well as LCSs that have been in Singapore recently, represent the bulk of vessels specifically outfitted for minesweeping duties that the Navy has available anywhere globally. Any mine-clearing operation in and around the Strait of Hormuz will include other naval vessels, as well.

As an aside, the Navy’s Lewis. B. Puller class Expeditionary Sea Base (ESB) ship USS John L. Canley, which is homeported in the U.S. Pacific territory of Saipan, was also spotted heading west past Singapore on March 23. That ship was subsequently tracked sailing in the Indian Ocean, raising questions about whether it might be headed to the Middle East, as well. None of the Navy’s three other ESBs has been observed heading toward that region recently.

USNS John L Canley and USNS Alan Shepherd passing Singapore just now heading to the Middle East

John L Canley is at Expeditionary Transfer Dock, seemingly carrying an Osprey and 3 Seahawk helicopters on top and then the Alan Shepherd is a dry Cargo vessel

Photo by me pic.twitter.com/anLsxJJDT1

— Singapore Ship Spotting (@sgshipspotting) March 23, 2026

A crisis scenario in and around the Persian Gulf, especially one involving Iran mining the Strait of Hormuz or otherwise threatening that critical waterway, was central to the Navy’s decision to acquire the ESBs in the first place. From the start, a key mission for the sea base ships has been serving, in part, as launch platforms for MH-53E Sea Dragon mine-hunting helicopters. At the same time, the Navy MH-53E fleet has dwindled in recent years to a single squadron, and the type is set to be completely retired by the end of 2027. Canley was seen with an apparent load of V-22 Osprey tiltrotors and MH-60 Seahawk helicopters on its deck as it passed by Singapore last month.

There has been talk in the past about ESBs acting as motherships for Avenger class mine-hunters. Canley be used to launch and recover uncrewed surface vessels (USV) and uncrewed underwater vehicles (UUV) as part of minesweeping and other operations, as well. In the context of the current blockade of Iranian ports, the ship could have a separate role as a valuable platform for staging visit, board, search, and seizure (VBSS) operations and otherwise supporting the current blockade of Iranian ports.

When it comes to the mission to clear Iranian naval mines, additional warships, as well as aircraft, will be needed just to provide critical force protection. This was already underscored by CENTCOM sending the two Arleigh Burke class destroyers through the Strait of Hormuz over the weekend. In February, before the war with Iran erupted, TWZ also called attention to the importance of force protection in these operations after A-10 Warthog ground attack aircraft conducted an exercise with the USS Santa Barbara in the Persian Gulf. A-10s have been prowling the Strait of Hormuz as part of operations against Iran.

How many naval mines Iran has actually laid, and of what types, is murky. In March, CBS News reported Iranian forces had seeded a number of Maham 3 and Maham 7 mines in and around the Strait of Hormuz. The Maham 3 is a so-called “influence mine,” designed to be triggered by the acoustic and/or magnetic signatures of a passing vessel, and that is moored in place. The Maham 7 is also an influence mine, but that sits on the seabed, and is therefore intended to be employed in shallower waters where it can still be set off by a ship sailing above. Naval analyst H. I. Sutton has more details on these and other Iranian naval mines here. Last Friday, The New York Times reported that Iran had lost track of the disposition of at least some of the mines it had laid, and that this was hampering efforts to reopen the Strait, citing unnamed U.S. officials.

Sweeping for naval mines is a slow-going and complex affair, in general, that carries significant risks even in benign environments. The dangers in case of the Strait of Hormuz are magnified now by the U.S. blockade of Iranian ports and the potential for the full resumption of hostilities with the regime in Tehran. U.S. and Iranian officials met this weekend in Pakistan following the announcement of a ceasefire last week. However, those talks ended after a day without any substantive progress toward a diplomatic resolution of the current conflict.

In the meantime, despite extensive U.S. and Israeli strikes over the past six weeks, Iran is still understood to have a significant array of capabilities, including anti-ship ballistic and cruise missiles, kamikaze drones, and uncrewed explosive-laden boats, that it could also use to turn the Strait of Hormuz into a super weapons engagement zone. TWZ previously explored these threats in greater detail in the context of past discussions about U.S. warships escorting commercial ships in and out of the Persian Gulf.

More about the mission to clear Iranian naval mines, including whether Japan-based Avenger class ships will take part and if the LCSs will finally return from the Pacific Theater, should become clearer in the coming days.

Contact the author: joe@twz.com

In a follow-up to our recent story about a pair of U.S. Navy Independence class Littoral Combat Ships (LCS) configured for minesweeping appearing in the Pacific, those vessels have now moved further east from Malaysia to Singapore. USS Tulsa and USS Santa Barbara remain thousands of miles away from their primary assigned operating area in the Middle East, where the conflict with Iran grinds on. The highly strategic Strait of Hormuz notably remains closed to normal maritime commerce due to Iranian attacks. Though the regime in Tehran does not yet appear to have employed naval mines to a large degree in the Strait, this remains a major threat that will factor into any plans to reopen the critical waterway.

As to why the Navy sent two of its three mine hunters in the Middle East not just out of the line of fire, but literally across the globe at a time when the U.S. and its allies could be facing the mining of one of the world’s most critical waterways remains a mystery.

U.S. Naval Forces Central Command (NAVCENT) has confirmed to TWZ that USS Tulsa and USS Santa Barbara are in Singapore. Last year, the Navy sent Tulsa and Santa Barbara, as well as a third Independence class LCS, the USS Canberra, to Manama in Bahrain in the Persian Gulf. Canberra‘s current location remains unclear. All three ships were explicitly sent to the Middle East to fill capability and capacity gaps left by the decommissioning of four Avenger class mine-hunters that had been deployed in the region for decades beforehand.

Local spotters had already caught the two LCSs arriving in Singapore earlier today. Authorities in Malaysia had previously confirmed that the LCSs had left the Port of Penang in that country on March 16. Singapore is a city-state that lies roughly 370 miles southeast of Penang.

“Tulsa and Santa Barbara are conducting scheduled maintenance and logistics stop in Singapore. The U.S. and Singapore navies have an excellent and longstanding defense relationship,” a NAVCENT spokesperson told TWZ. “A testament to this relationship is the agreement to allow littoral combat ships to operate primarily from Singapore as a logistics and maintenance hub, as well as supporting regular port visits and logistics stops for other U.S. ships.”

NAVCENT had given TWZ an almost identical statement when asked previously about the arrival of the LCSs in Malaysia:

“Tulsa and Santa Barbara are conducting brief logistical stops in Malaysia. U.S. forces routinely make port calls in Malaysia as part of our operations, reflecting the close and enduring military cooperation between the United States and Malaysia.”

“These stops allow for logistical arrangements such as replenishments,” Malaysian Defence Minister Datuk Seri Mohamed Khaled Nordin separately told the New Strait Times newspaper yesterday. “Any foreign naval vessel must submit a request through its country to the Royal Malaysian Navy, which forwards it to the Foreign Ministry for approval.”

When Tulsa and Santa Barbara left the Middle East, to begin with, is unclear. There is no evidence of any U.S. warships having been in port in Bahrain since at least February 23, five days before joint U.S. and Israeli strikes on Iran began. Manama was almost immediately subjected to retaliatory attacks, making clear that sending American vessels elsewhere was, broadly speaking, a prudent security measure.

How long Tulsa and Santa Barbara will remain in Singapore, and where they might head to next, remains to be seen. As NAVCENT’s statement noted, Singapore’s Changi Naval Base has been a hub for forward-deployed LCSs in the Indo-Pacific region. U.S. naval vessels, in general, regularly make port calls there, including for maintenance.

As an aside, online ship tracking data indicates that the America class amphibious assault ship USS Tripoli and the San Antonio class amphibious warfare ship USS New Orleans are also now sailing through the same general area. The Tripoli Amphibious Ready Group (ARG) is reportedly on its way to the Middle East, loaded with Marines, as you can read more about here.

Regardless of where they might head next, Tulsa and Santa Barbara have now moved even further away from their assigned station in the Middle East. This, in turn, means that two of three mine countermeasures ships that are supposed to be forward-deployed in that region, at least, are currently in an entirely different part of the world. Whether any other LCS or other ships configured for the mine countermeasures mission have been deployed closer to the Middle East, or are now on their way, is unknown. There are only four other Avenger class ships still in Navy service, all of which are in Japan and have been slated for decommissioning in the coming years.

Generally speaking, the Independence class LCS is a far more advanced ship, overall, than the Avenger class mine hunter. When suitably equipped, the LCSs also offer new standoff mine countermeasures capabilities, including uncrewed mine-sweeping drone boats and helicopter-borne systems. It should be noted that the Navy had originally planned for both Independence and Freedom class LCSs to be readily configured and reconfigured for different operational needs using an array of different mission packages, or ‘modules.’ The service now deploys LCSs in static configurations.

Still, questions continue to be raised whether LCSs fitted out for the mine countermeasures role are adequate replacements for ships purpose-built for this mission set, as you can read about in much more detail in our past reporting. Mine-clearing operations are complex and slow-going affairs that carry significant risks even in optimal conditions in benign environments.

As noted, Iranian naval mines have yet to make a major appearance in the current conflict. U.S. officials have largely downplayed the mine threat, especially when compared to the active ongoing attacks Iran has been launching on commercial ships in and around the Strait of Hormuz using drones, missiles, and uncrewed boats.

That being said, “we defend all these countries and then, ‘do you have any minesweepers?’ And they say, ‘Well, would it be possible for us not to get involved?’” U.S. President Donald Trump said earlier this week in response to a question from a reporter about the current conflict with Iran. This suggested that American officials had at least asked allies and partners about the possibility of them providing additional naval mine countermeasures capabilities to the region. If so, this is somewhat puzzling, coming as the Navy had sent the two LCSs to another hemisphere.

Trump had previously appealed publicly for assistance, in general, in reopening the Strait of Hormuz, but had been soundly rejected by a number of countries. The President then said yesterday that any help was no longer required.

“I wonder what would happen if we ‘finished off’ what’s left of the Iranian Terror State, and let the Countries that use it, we don’t, be responsible for the so called ‘Straight?’ [sic],” Trump then wrote just earlier today in a post on his Truth Social site. “That would get some of our non-responsive ‘Allies’ in gear, and fast!!!”

In an interview last Thursday with CNBC, U.S. Energy Secretary Chris Wright had said the prospect of U.S. Navy warships escorting commercial vessels through the Strait of Hormuz was still weeks away, at best. TWZ previously explored how risky such an operation would be, given Iran’s ability to turn the waterway into a super weapons engagement zone where mines would be just one of many concerns.

The fact that USS Tulsa and USS Santa Barbara have moved even further from the Middle East only underscores questions about what the U.S. government’s line of thinking might be now about how to get maritime commerce flowing again in and out of the Persian Gulf.

Contact the author: joe@twz.com

The U.S. Navy Independence class Littoral Combat Ships (LCS) USS Tulsa and USS Santa Barbara, which are configured for minesweeping duties, have appeared in port in Malaysia. Both of these ships were last known to be forward-deployed in the Middle East, having arrived in Bahrain in the past year or so to take the place of a group of now-decommissioned Avenger class mine hunters. Now, as Iranian attacks on commercial ships have caused a virtual halt to maritime traffic through the highly strategic Strait of Hormuz, these ships have emerged thousands of miles away. The extent to which Iran has seeded naval mines in the Strait already is unclear, but this remains a huge threat to the future security of the waterway and will have to be taken into account in any future effort to reopen this critical waterway.

A spotter in Malaysia posted pictures of the USS Tulsa and USS Santa Barbara, which are said to have been taken today at the North Butterworth Container Terminal (NBCT) in the Port of Penang. Mike Yeo, an Australia-based defense and aviation reporter, was among the first to call attention to the particular significance of the images. TWZ has reached out for more information.

USS Tulsa and USS Santa Barbara are among a select number of Independence class LCSs fitted with a mine countermeasures mission package, or “module.” In its current form, the package includes towed mine-hunting sonar for the ships, Common Unmanned Surface Vehicles (CUSV) with mine-sweeping gear, and mine detection and neutralization systems carried by embarked MH-60 Sea Hawk helicopters. We will come back to this configuration later on.

CUSV®

Airborne Laser Mine Detection System (ALMDS) Video

When it comes to why the ships are now in Malaysia, TWZ also reached out to U.S. Central Command (CENTCOM), which directed us to the U.S. Navy’s Fifth Fleet. We were then directed by Fifth Fleet back to CENTCOM. CENTCOM is the top U.S. military command for operations in the Middle East. Fifth Fleet is the Navy’s numbered fleet in the Middle East, with its commander dual-hatted as head of Naval Forces Central Command (NAVCENT). Fifth Fleet and NAVCENT are headquartered in Manama, Bahrain, in the Persian Gulf.

We have reached out to the U.S. Navy and U.S. Indo-Pacific Command (INDOPACOM), as well.

Pictures available through the U.S. military’s Defense Visual Information Distribution Service (DVIDS) show USS Tulsa was in port in Bahrain at least as of February 9. Separate images also show USS Santa Barbara operating in the Persian Gulf on January 30. The current disposition of a third Independence class LCS, the USS Canberra, which had also been forward-deployed in the Middle East at least as of January, is unknown. Whether any other mine countermeasures ships may not be headed to the Middle East is also not known.

A review of satellite imagery in Planet Labs’ commercial archive shows no evidence of any U.S. warships being in port in Mamana since February 23. The United States and Israel launched their joint operation against Iran on February 28.

Moving U.S. warships out of port in Bahrain ahead of the current conflict was a prudent security measure. The Gulf state is well within range of Iranian missiles and long-range kamikaze drones, and U.S. military facilities in Manama did subsequently come under attack. The U.S. military’s own strikes on Iranian naval vessels in port have underscored the vulnerability of ships sitting pierside.

Why the decision was made to then send the USS Tulsa and USS Santa Barbara thousands of miles to the east is unknown. A host of factors may have come into play, including the availability of suitable friendly ports and diplomatic considerations.

Regardless, at least two-thirds of the warships intended to be available for tasking for mine countermeasures missions in the Middle East are presently in a completely different part of the world. As noted, USS Tulsa, USS Santa Barbara, and USS Canberra, were forward-deployed to the region in the first place explicitly to fill gaps left by the decommissioning of four Avenger class mine hunters last year. The former USS Devastator, USS Dextrous, USS Gladiator, and USS Sentry left the region for good aboard a heavy lift ship in January. There are only four Avenger class ships left in active Navy service, all of which are forward-deployed in Japan, and are also slated to be decommissioned in the coming years.

How many of the Navy’s Independence class LCSs, in total, have been configured for the mine-clearing mission to date is unknown. In addition to USS Tulsa, USS Santa Barbara, and the USS Canberra, the USS Kansas City was at least being fitted out with this mission module as of last year.

The Independence class LCS is a far more advanced ship than the Avenger class mine hunter, and does offer new standoff mine countermeasures capabilities, including aforementioned CUSV drone boats and helicopter-borne systems. Still, questions continue to be raised about whether metal-hulled LCSs with mine countermeasures packages are adequate replacements for ships purpose-built for this mission. As TWZ previously wrote back in January:

The [Avenger class] ships themselves have fiberglass-coated wooden hulls to reduce their own vulnerability, particularly to mines that detect targets by their magnetic signature.

The Navy has long intended to replace the Avenger class ships with LCSs configured for the mine countermeasures duties. However, delays with the LCS mine countermeasures and other mission packages, or “modules,” as well as other persistent issues with both subclasses of those ships, repeatedly delayed those plans. The LCS program had also originally envisioned it being possible to readily reconfigure the ships for different mission sets by swapping out modules. However, the Navy is now deploying LCSs in largely fixed configurations.

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Questions and criticism about the suitability of metal-hulled LCSs to take on the mine countermeasures mission have come up in the past. Both subclasses of LCS are also much larger than the Avenger class design, which could impose limits on how close they can get to mined or potentially mined areas. LCSs are better able to defend themselves against other threats than the Avengers, but they still have relatively limited firepower, which has been a separate source of criticism for years now. There would still be a significant need for tertiary support to protect LCSs during mine-clearing operations, which are slow and complex, and carry significant risks, even in benign environments.

In May 2025, a top U.S. Navy mine warfare officer gave an unclassified briefing detailing significant ongoing issues with the LCS mine countermeasures, according to a story published just this past week by Hunterbrook Media. Copies of the briefing slides that the outlet published say that employing the CUSV requires hours of prep time, and that the drone boat’s sonar sometimes has trouble spotting threats, but that the operators may have no indication of this until data is assessed after a mission. Visual confirmation of mines using the AN/AQS-20 mine-hunting system has also proven challenging “even [in] the relatively benign turbidity of SoCal [Southern California] waters,” another slide explains. The briefing also highlighted a number of potential “single-point failures” both in terms of mine countermeasures systems included in the module, and the equipment required to deploy and recover them.

Lastly, and perhaps most importantly, one of the briefing slides noted that “LCS was designed as a multi-mission platform” and “all of these other missions reduce time for the ship and Minemen to gain proficiency in MCM [mine countermeasures].” To reiterate, the Avenger class ships were purpose-built for this mission set and had crews trained to match. Mine-clearing operations are slow and complex, and carry significant risks, even when carried out by experienced personnel in benign environments.

In the context of the current conflict, there have been reports in the past week or so saying Iran has at least attempted to lay mines in and around the Strait of Hormuz. The U.S. military also says it has been actively targeting mine-laying assets. At the same time, Iran has laid mines in and around the Persian Gulf in the past, and this remains a real point of concern. Iranian anti-ship cruise and ballistic missiles, kamikaze drones, and uncrewed explosive-laden boats further complicate the threat picture for commercial vessels and any warships attempting to help clear the way.