Iran promises major retaliation, but neither Israel nor Iran wants a major shooting war, given the stakes for both countries. Even so, the danger of a miscalculation is ever-present, as both countries press for advantage in Gaza and southern Lebanon.

The Iranian officials who were killed had been deeply engaged in arming and guiding proxy forces in Gaza, Lebanon, Syria, Iraq and Yemen as part of Iran’s clearly stated effort to destabilize and even destroy the Jewish state.

For Israel’s prime minister, Benjamin Netanyahu, who presumably approved such a sensitive attack, the successful elimination of such key Iranian military figures is a political coup. It comes at a time when demonstrations calling for his resignation have increased in intensity, as the war against Hamas drags on and Israeli hostages remain in Gaza.

Displaying its ability to infiltrate Iranian intelligence, Israel is trying to hit the operational part of Iran’s regional proxies, its so-called Axis of Resistance to Israel, aiming to weaken and deter them, even as the war in Gaza continues.

Mr. Netanyahu has emphasized for years that Israel’s main enemy is Iran and its nuclear program, and this strike may help him “rehabilitate his reputation as ‘Mr. Security,’” said Sanam Vakil, director of the Middle East and North Africa program at Chatham House.

But that will be difficult to pull off, she said, with Israel bogged down in Gaza, Hamas so far unbeaten and Iran and its proxies undiminished. For the same reasons, Mr. Netanyahu and the Israeli military want to weaken and deter Iran’s proxies, but without sparking a full-scale war with Hezbollah, the Iran-backed group that controls southern Lebanon and has been trading sporadic fire with Israel across the border.

Iran has vowed retaliation and revenge for what it called an unprecedented attack, but it is also in a bind, analysts argue.

U.S. officials do not believe that Iran initiated the Hamas attack or was even informed about it in advance, and since Oct. 7 “Iran has been clear that it does not want a regional war,” Ms. Vakil said. “It sees this conflict with Israel playing out over a longer time frame.”

“But this strike will be difficult for Iran to ignore,” she added, “because it is a direct attack on its territory” and killed three senior commanders of Iran’s Quds Force, the external military and intelligence service of the Islamic Revolutionary Guards Corps.

Iran said the Israeli strike killed an Iranian general, Mohammad Reza Zahedi, along with his deputy, a third general and at least four other people, reportedly including senior officials of Palestinian Islamic Jihad, an Iranian affiliate that is also fighting in Gaza.

The killing of General Zahedi, who was said to be in charge of Iran’s military relationship with Syria and Lebanon, is widely considered the most important assassination of an Iranian leader in years.

Yaakov Amidror, a former Israeli national security adviser, called the death of General Zahedi “an enormous blow to Iran’s immediate capabilities in the region.” He had helped oversee Iran’s attempt to build a “ring of fire” around Israel via its militant proxies while keeping Tehran’s involvement at arm’s length, Mr. Amidror said.

But how and when Iran chooses to retaliate will further raise the stakes. The most obvious recent example is its response to the assassination four years ago by the United States of Qassim Suleimani, the commander of the Quds Force. Then, Iran launched a major missile attack against an American base in Iraq, but only after warning of the attack in advance. There were no immediate U.S. casualties, though more than 100 military personnel suffered traumatic brain injuries, the Pentagon later said.

An anxious Iran, on high military alert, also shot down a Ukrainian passenger jet, killing 176 people, believing it to be an enemy plane.

Recently Iran has tried to de-escalate the tensions in its relationship with the United States after a January drone attack on a U.S. military base on the Jordanian-Syrian border killed three American soldiers.

But Iran may be more willing to risk a military escalation with Israel.

It could make other choices — a major cyberattack on Israeli infrastructure or its military, a barrage of rockets from southern Lebanon, a similar assassination of an Israeli commander, an attack on an Israeli embassy abroad, or another sharp acceleration of its nuclear-enrichment program.

The last would be a kind of direct riposte to Mr. Netanyahu, who has long warned about the danger of a nuclear-armed Iran and vowed to prevent it from happening. (Iran has always insisted that its nuclear program is purely peaceful, even as it has enriched uranium to close to weapons grade.)

Or Iran could bide its time. Mr. Amidror, the former Israeli national security adviser, said he doubted the strike would lead to a broader escalation between Israel and Iran, such as an all-out war involving Hezbollah along Israel’s northern border.

“Their interests haven’t changed in the aftermath. They’ll look for revenge, but that’s something else entirely,” he said, and it does not have to be limited to the immediate region.

One previous example he cited was the 1992 bombing of the Israeli embassy in Buenos Aires by Islamic Jihad, which killed 29 people and came in response to Israel’s assassination of the Hezbollah leader Abbas al-Musawi.

Aaron Boxerman contributed reporting from Jerusalem.