But analysts say that Iran likely will launch its own attack, raising fears of a regional war and showing the limits of US deterrence efforts in the Middle East.

The brinkmanship and resulting tensions have put further strain on Washington’s foreign policy. Already, the US is caught between two seemingly conflicting priorities: offering unconditional support for Israel and preventing the conflict in Gaza from expanding.

“Biden is doubling down on a formula that so far has been absolutely disastrous,” said Trita Parsi, executive vice president at the Quincy Institute, a think tank that promotes diplomacy.

Parsi said Biden should have rebuked Israel for attacking the Iranian embassy on April 1, violating international law and endangering US troops in the region.

But, he explained, the Biden administration is rewarding the Israeli government by promising to support it instead.

The US — unlike some of its Arab and Western allies — has not condemned the Israeli strike on the Iranian diplomatic facility in Syria, which killed seven members of the Islamic Revolutionary Guard Corps (IRGC), including two generals.

The White House, however, was quick to distance itself from the strike, stressing that the US was not involved in it.

US ‘devoted’ to Israel’s defence

US diplomats have reportedly been working the phones this week, speaking with their counterparts across the world to urge restraint from Iran.

While calling for de-escalation, US officials have also reaffirmed their country’s “ironclad” support for Israel, raising fears of a direct confrontation between Washington and Tehran.

“We are devoted to the defence of Israel. We will support Israel. We will help defend Israel, and Iran will not succeed,” Biden said on Friday. The Pentagon and State Department have also expressed similar positions.

“This completely deprives Israel of any incentives to de-escalate,” Parsi said.

He added that Biden’s backing of Israel mirrors his “bear hug” approach to Israeli Prime Minister Benjamin Netanyahu at the outset of the war on Gaza, which gave a green light to the mass killings and rights violations in the Palestinian territory.

“That helped shape Israel’s strategy that knew no limits, that did not care about international law — because they had come to understand that Biden will support them no matter what,” Parsi told Al Jazeera.

Sina Toossi, a senior fellow at the Center for International Policy think tank, called the US approach to the crisis “hypocritical and contradictory”.

“They’re calling on all the other parties in the region to be restrained, constantly telling the Iranians ‘don’t escalate’, whereas they encourage Israelis to act with total impunity,” Toossi told Al Jazeera.

Iran says Israel ‘must be punished’

He added that the Iranian pledge to retaliate is partly driven by the perception that the US and Israel believe they can cause harm without triggering a strong reaction from Tehran, which does not want a regional war.

But now Iran wants to draw a firm line, Toossi told Al Jazeera. “It can very objectively be stated that US policy has gotten us into this situation.”

The Israeli military has been targeting Iran-linked sites in Syria for years, as Tehran bolsters its military presence in the war-torn country.

But experts say Tehran saw bombing a diplomatic facility as a particularly brazen act that should not go unanswered.

“The consulate and embassy offices in any country are considered to be the territory of that country. When they attack our consulate, it means they have attacked our territory,” Iranian Supreme Leader Ali Khamenei said on Wednesday.

“The Zionist regime made a mistake and must be punished and will be punished.”

It remains to be seen where and how that promised punishment will come, but if it happens, it could be a turning point in the expanding Gaza conflict. Several countries have warned their citizens this week against travelling to the region.

The war on Gaza, which has killed more than 33,000 Palestinians, has already expanded beyond the narrow enclave.

Iran-allied Lebanese group Hezbollah has been exchanging fire with Israeli forces daily. The Houthis have been firing missiles and drones at Israel-linked ships in the Red Sea, demanding an end to the war, and a US-led coalition has been targeting the Yemeni group to stem its attacks.

But the trend towards regional escalation appeared to have subsided somewhat after Iraqi armed groups halted their attacks on US bases in Iraq and Syria — at the request of Tehran, according to several media reports.

A drone attack by Iran-backed Iraqi groups had killed three US soldiers at a base near the Jordan-Syria border. The US had then retaliated with a series of strikes in Iraq and Syria, but the crisis was eventually contained.

‘Pressure’ on US and Israel

Now the region is once again staring at the prospect of a widened conflict.

“The pressure is now on Israel and the US rather than Iran. And yes, there are a lot of threatening remarks directed at Iran in the hope that the Iranians don’t act. But the die was first cast by Israel,” said Vali Nasr, a professor of international affairs at John Hopkins University.

“And now people are trying to avoid what might be consequences.”

Biden does not want the US to be pulled into a war with Iran, particularly as he seeks reelection in November. But Washington’s default policy has long been to support Israel, Nasr added.

“The American position is that they don’t want the war to expand. They don’t want to be dragged into a war with Iran. They don’t want the Gaza war to become a regional war,” he told Al Jazeera.

“They may be saying things to Israel behind the scenes, but I think publicly they’re trying to warn Iran not to escalate the war as well.”

But he added that every country has to contend with domestic politics in its foreign policy. “And in the United States, giving ironclad guarantees to Israel’s defence is already a given.”

In Washington, Iran hawks are urging a forceful American response if Israel is attacked.

Republican Senator Tom Cotton called on Wednesday for “joint American-Israeli retaliation” that would be “swift and devastating” to any Iranian military move against Israel.

Israel is under threat of imminent attack by Iran. President Biden needs to warn the ayatollahs immediately that the United States will back Israel to the hilt and the joint American-Israeli retaliation for any attack will be swift and devastating.

— Tom Cotton (@SenTomCotton) April 11, 2024

‘Obvious de-escalatory path’

Ryan Costello, policy director at the National Iranian American Council (NIAC), a Washington, DC-based group that favours US diplomacy with Iran, warned that if the US joins Israel in reprisal strikes, the results could be catastrophic.

“It’s really reckless and would certainly plunge the entire region into a disastrous and bloody conflict,” he told Al Jazeera.

Costello said the US posture so far has been heavy on deterrence and light on de-confliction.

“They’re saying Israel is going to have our backing, and Iran should just accept the strike on a diplomatic compound, which I think would be hard for any nation to accept,” he said.

For his part, Parsi of the Quincy Institute stressed that the best remedy to the simmering tensions across the Middle East is ending the war in Gaza.

“In the broader picture, there has of course been an obvious de-escalatory path that has always been available to Biden, and that is to push for a ceasefire in Gaza,” Parsi said.

“A ceasefire would have stopped the attacks by Iraqi militias on the US, would have stopped the Houthi attacks, would have stopped the escalation between Iran and Israel and Israel and Hezbollah.”