BEIRUT — Israel’s military was on high alert Thursday as the country braced for Iran’s promised revenge after an Israeli strike in Damascus this week killed senior Iranian commanders and stirred fears of widening war across a region on edge.

The strike — in broad daylight, on a diplomatic building adjacent to Iran’s embassy in Syria — was an escalation in Israel’s multi-front battles against Iranian-backed groups, which have intensified during its war in Gaza. The Israeli strike drew threats of retaliation from Tehran’s leaders and condemnation from their Arab neighbors. The European Union, which also condemned the strike, said in a statement that “further escalation in the region is in no one’s interest.”

“We will make them regret this crime and other similar ones with the help of God,” Iran’s supreme leader, Ayatollah Ali Khamenei, said in a statement Tuesday, the day after the attack.

For all of Iran’s muscular rhetoric, though, it would probably carefully calibrate any response, according to analysts, Western officials and people close to Iranian-backed militant groups. The country still hoped to avoid being goaded into a costly war, they said, while maintaining its ability to support proxy forces that have traded fire with Israel and attacked its main ally, the United States, throughout the Middle East.

The Iranians “believe the Israelis are intentionally dragging them into reacting, to spark a regional war or expand the current one,” said a person associated with Hezbollah, the Lebanese militant group and political party that is backed by Iran.

The Damascus strike was viewed as an attack on Iranian soil and, as a result, any retaliation would be likely to come from Iran itself, rather than its allies, said the person, who spoke on the condition of anonymity because of the sensitivity of the matter.

Israel will be “punished by the hands of our brave men,” Khamenei said, also suggesting retribution was a sovereign affair.

The Damascus attack was the most significant strike on Iranian interests since the start of the Gaza war, following the Oct. 7 attack on southern Israel by Hamas, another of Iran’s regional allies.

Among the dead Monday were two senior members of Iran’s Islamic Revolutionary Guard Corps, along with five officers, according to a statement from the IRGC. One of the commanders, Mohammad Reza Zahedi, had been identified by the U.S. Treasury Department in 2010 as a conduit between Iran, Hezbollah and Syrian intelligence.

The targets and their location — in a diplomatic facility, traditionally exempted from hostilities — made the attack especially brazen.

The United States was quick to deny involvement. “We had nothing to do with it,” John Kirby, the National Security spokesman, said at a press briefing Tuesday.

It came after months of regional instability reverberating from the Gaza war. In Lebanon, Iraq, Syria and Yemen, confrontations have simmered between Iranian-backed groups and Israel or the United States — a pattern of violence just short of all-out war, which analysts and U.S. officials say Tehran has sought to avoid.

For months, though, there have been warnings that the region is one miscalculation away from calamity.

Events began to spiral in January, after an attack by fighters allied with Iran killed three U.S. service members at a base in Jordan.

The United States retaliated with airstrikes against Iranian-backed militias in Iraq. Rather than escalating further, Tehran called for a halt to what had been regular assaults by the Iraqi militias on U.S. bases. The Pentagon acknowledged the apparent pause, a sign that the tacit rules of engagement had been restored.

But whatever understanding may have been reached was now threatened by Monday’s strike in Damascus, according to the person close to Hezbollah, saying it “sabotaged” previous understandings between Iran and the United States. “Iran is seeking a price for what happened,” the person said.

The most recent annual report on global security threats from the Office of the Director of National Intelligence, published in February, noted that Tehran remained “careful” to avoid head-to-head fighting with Israel and the United States, choosing instead to enable Hezbollah forces in Lebanon, Houthi fighters in Yemen, and a network of proxy militias in the region. U.S. officials said there was no indication that the Israeli strike Monday had changed that assessment.

But U.S. officials have become increasingly concerned that the daily exchange of fire between Hezbollah and Israel on the country’s northern border could escalate into a full-scale conflict.

The strike on the Quds Force officers, while provocative, didn’t rate as the kind of mass-casualty event that would trigger that broader conflict, four U.S., Israeli, and other Western officials said this week. One senior Israeli security official said he did not expect

Iran to “overreact,” noting this was not the first attack Israel had carried out in Syria against Iran and its affiliates.

The officials, who spoke on the condition of anonymity to discuss sensitive intelligence and security matters, expected Iran to respond with drone or missile attacks on Israeli targets, calibrated to avoid an even bigger response from Israel.

Still, in such a combustible environment, the potential for mistakes was high, they acknowledged.

Alon Pinkas, a veteran Israeli diplomat and former senior-level adviser who has been critical of Israeli Prime Minister Benjamin Netanyahu’s government, called Israel’s decision to strike Iran directly “both warranted and justifiable,” given its “constant, broad and menacing” sponsorship of proxy militias.

“But for the same reason, it may also precipitate escalation because this type of attack may be impossible for Iran to contain,” he said.

Israel appeared to be preparing for retaliation. The Israeli military announced Thursday that it was suspending leave for reservists, a day after it ordered the reinforcement of air defense units. Later Thursday, to avoid panic, the Israel Defense Forces spokesman wrote in a message posted on X that “no generators need to be purchased, no food should be stored, no money should be withdrawn from ATMs.”

By striking the Iranian diplomatic compound, “Israel is prepared for the broader backlash that could lead to the regional war,” said Sanam Vakil, director of the Middle East and North Africa program at London’s Chatham House.

A broader war was “not the original motivation,” she said, but rather part of an Israeli strategy aimed at destabilizing the Iran’s “axis of resistance” through a campaign of assassinations, similar to those carried out in the past by Israel’s intelligence service, the Mossad.

“It’s not just about Hamas. It’s about everyone at once,” she said, adding that Israel was also keenly aware that its window for such operations was limited, as the death toll soared in Gaza and its military tactics came under greater scrutiny.

In Iran, the debates were over the virtues of a direct strike, or rather “taking time and exhausting Israel” with the kind of low-level warfare it was currently conducting, Vakil said. It was possible that Syria could serve as an arena for heightened hostilities between

Israel and Iran, or that Tehran could “pivot and become confrontational in a different arena,” she said.

Afshon Ostovar, a professor of national security affairs at the Naval Postgraduate School, said that while the Damascus strike was serious, “I don’t think it is game-changing. I think it’s a very gradual escalation of the tit-for-tat conflict that has been going on between Israel and Iran over decades,” he said.

Even if the attack doesn’t bring Iran into direct conflict with Israel and the United States, it highlights growing tensions between Iran’s political and military ambitions.

Iran was “hamstrung because it is on the one hand succeeding politically ... but it can’t really push any harder militarily,” he said, referring to Tehran’s satisfaction at Israel’s increasing international isolation and the growing sympathy for Palestinians.

For Iran, escalating military operations risked “blowback” that wouldn’t benefit the leadership in Tehran.

“So long as Iran wants to succeed politically, it has to take some of this stuff on the chin,” he said. “For Iran, there’s no real reason to change the game and get into a shooting war.” George reported from Dubai and Harris from Washington.

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