Despite the sanctions and military strikes, including a large-scale operation Friday carried out by U.S. and British warships and warplanes that hit more than 60 targets across Yemen, the Houthis are continuing their harassment campaign of commercial and military ships. The latest incident occurred Wednesday when a one-way attack drone was launched from a Houthi-controlled area in Yemen and struck the Marshall Islands-flagged, U.S.-owned and -operated M/V Genco Picardy in the Gulf of Aden.

The U.S. has also strongly warned Iran to cease providing weapons to the Houthis. On Thursday a U.S. raid on a dhow intercepted ballistic missile parts the U.S. said Iran was shipping to Yemen. Two U.S. Navy SEALs remain unaccounted for after one was knocked off the vessel by a wave during the seizure and the second followed the overcome SEAL into the water.

On Wednesday, Pentagon Press Secretary Maj. Gen. Pat Ryder said the U.S. would continue to take military action to prevent further attacks.

“They are exploiting this situation to conduct attacks against the ships and vessels from more than 50 countries … around the world. And so we’re going to continue to work with our partners in the region to prevent those attacks or deter those attacks in the future,” Ryder said.

There have been several incidents since the Friday joint operations. The Houthis fired an anti-ship cruise missile toward a U.S. Navy destroyer over the weekend, but the ship shot it down. The Houthis then struck a U.S.-owned ship in the Gulf of Aden on Monday and a Malta-flagged bulk carrier in the Red Sea on Tuesday. In response Tuesday, the U.S. struck four anti-ship ballistic missiles that were prepared to launch and presented an imminent threat to merchant and U.S. Navy ships in the region.

Hours later, the Houthis claimed responsibility for the attack on the Malta-flagged bulk carrier Zografia. The ship was hit, but no one was injured and it continued on its way.