The fierce fighting between Israel and Iran has deepened as the United States considers whether to enter the conflict.

President Trump called on Tuesday for Iran’s “unconditional surrender,” cited the possibility of killing its supreme leader and referred to Israel’s war efforts with the word “we.”

On Tuesday, in a social media post, Mr. Trump wrote, “We know exactly where” Ayatollah Ali Khamenei, Iran’s supreme leader, “is hiding.” But he added, “We are not going to take him out (kill!), at least for now.” He also boasted of Israel’s air superiority, suggesting that it was based on American technology.

Israeli officials have been pressing the United States to engage directly in the war by dropping its huge bunker-busting bomb, the Massive Ordnance Penetrator, which is thought to be the only weapon powerful enough to take out Iran’s buried Fordo nuclear site.

Should the United States join the war, Iran has prepared missiles and other military equipment for possible retaliatory strikes on U.S. bases in the Middle East, according to American officials who have reviewed intelligence reports.

The fighting began last week, when Israel launched a surprise attack on dozens of targets inside Iran, including nuclear sites, and killed many of the Iranian military’s top leaders.

For nearly two decades, Israel avoided all-out war with its biggest enemies.

It fought contained conflicts with Hamas, but ultimately allowed the group to retain power in Gaza. It maintained an uneasy calm with the Lebanese militia Hezbollah, even as its fighters entrenched themselves in southern Lebanon. And despite planning a major assault on Iran, it limited its attacks to smaller, clandestine operations.

Israel’s massive, ongoing assault on Iran highlights an extraordinary shift in Israeli military doctrine since Hamas, Iran’s Palestinian ally, attacked the country in October 2023. It is a change that has redrawn the power dynamics in the Middle East, unraveled Iran’s regional alliance and enshrined Israel as the dominant military force in the region.

Having given Hamas years to prepare for the Oct. 7 attack, Israel reversed course afterward to unleash one of the most destructive campaigns in recent warfare. It then assassinated most of Hezbollah’s leadership and decimated large parts of southern Lebanon. Now, in Iran, it is carrying out the kind of broad and brazen attack that it long threatened but never dared to enact.

“We are changing the face of the Middle East,” said Prime Minister Benjamin Netanyahu of Israel during a press briefing on Monday. “And this could lead to far-reaching changes within Iran itself,” he added.

Israel said it had killed a newly installed senior Iranian military official on Tuesday, just days after his predecessor was slain, further destabilizing Iran’s military chain of command as the war entered its fifth day.

Since Israel began bombing Iran on Friday, it has killed at least 11 senior generals while striking Iranian nuclear sites and missile launchers, in what it calls an effort to prevent Iran from developing a nuclear weapon.

On Tuesday morning, the Israeli military said it had killed Maj. Gen. Ali Shadmani, describing him as the most senior military commander in Iran. He was appointed to his post four days ago, replacing a general who was killed by Israel on the first day of hostilities. Iran did not immediately comment on Israel’s claim about General Shadmani. If confirmed, his death would deal yet another blow to Iran’s beleaguered military leadership.

A senior Israeli defense official said that the killing of General Shadmani reflected Israel’s decades-long effort to infiltrate Iran’s intelligence services, as well as the careless mistakes senior Iranian officials have been making as they try to flee Israeli attacks.

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Smokes after Israeli airstrikes in Tehran on Tuesday. In Iran, Israel is carrying out the kind of broad and brazen attack that it long threatened but never dared to enact before.

For nearly two decades, Israel avoided all-out war with its biggest enemies.

It fought contained conflicts with Hamas, but ultimately allowed the group to retain power in Gaza. It maintained an uneasy calm with the Lebanese militia Hezbollah, even as its fighters entrenched themselves in southern Lebanon. And despite planning a major assault on Iran, it limited its attacks to smaller, clandestine operations.

Israel’s massive, ongoing assault on Iran highlights an extraordinary shift in Israeli military doctrine since Hamas, Iran’s Palestinian ally, attacked the country in October 2023. It is a change that has redrawn the power dynamics in the Middle East, unraveled Iran’s regional alliance and enshrined Israel as the dominant military force in the region.

Having given Hamas years to prepare for the Oct. 7 attack, Israel reversed course afterward to unleash one of the most destructive campaigns in recent warfare. It then assassinated most of Hezbollah’s leadership and decimated large parts of southern Lebanon. Now, in Iran, it is carrying out the kind of broad and brazen attack that it long threatened but never dared to enact.

“We are changing the face of the Middle East,” said Prime Minister Benjamin Netanyahu of Israel during a press briefing on Monday. “And this could lead to far-reaching changes within Iran itself,” he added.

For now, that second claim remains unproven. The Israeli military campaign has weakened Iran, but it has not yet destroyed the country’s nuclear program or collapsed its government, and it may still fall short of both. The war could also devolve into an intractable quagmire with no exit strategy or offramp.

Image Iranians lined up at gas stations in Tehran on Monday. Credit… Arash Khamooshi for The New York Times

Mr. Netanyahu’s broader point is harder to contradict. Hamas is no longer a threat to Israel. Hezbollah’s influence over Lebanon — let alone the danger it poses to Israelis — is much diminished. The government in Syria, a pillar of Iran’s regional alliance, was overthrown last December, in part because Hezbollah could no longer come to its aid.

These tectonic shifts also speak to a vast change within the Israeli psyche and strategic outlook since Hamas’s attack in October 2023.

For Israel’s critics, the attack was the inevitable consequence of the country’s blockade of Gaza, occupation of the West Bank, and failure to resolve the Palestinian conflict through diplomatic concessions. Many Israelis have drawn the opposite conclusion: They believe that the October attack — the deadliest in Israeli history — stemmed from Israel’s failure to pre-emptively and decisively defeat its enemies.

“In the 20 years before Oct. 7, we allowed threats to develop beyond our borders, trusting that our intelligence would give us prior warnings of any attack,” said Maj. Gen. Amos Yadlin, a former head of Israeli military intelligence.

“The trauma of Oct. 7 completely changed that mind-set and made us willing to take risks that we didn’t take in the past,” General Yadlin said. “We will no longer wait to be attacked, and we will not wait to be surprised.”

The approach echoes Israel’s strategic outlook in the early decades of its existence, when it often acted more swiftly and decisively to remove threats on its borders, General Yadlin said. The clearest example was in June 1967, when Israel pre-emptively attacked Egypt after the Egyptian military moved troops toward the Israeli border.

Image Israeli fighter aircraft over the Sinai Peninsula of Egypt in June 1967. Israel’s current approach in the Middle East echoes its strategic outlook in the early decades of its existence, when it often acted swiftly and decisively to remove threats on its borders. Credit… Israel Defense Forces, via Agence France-Presse — Getty Images

“As Egypt massed troops on our southern border, we did not wait to be surprised,” General Yadlin said. “Now, we are reviving that doctrine.”

Israel’s new approach is the culmination of months of re-evaluation, during which the military’s confidence — crushed by the failures of Oct. 7 — was gradually restored.

While Israel’s approach to Hamas was immediately wrathful, the country was initially wary of taking on Hezbollah and Iran. Mr. Netanyahu called off a pre-emptive attack on Hezbollah in the first week of the war in 2023, amid fears that Israel would struggle to maintain a multi-front war against the Iran-led alliance.

For nearly a year, Israel fought only a low-level border conflict with Hezbollah. Despite increasing clashes with Tehran in 2024, Israel limited its strikes on Iran to avoid an all-out conflict.

Israel’s approach began to change last September, when a sequence of unexpected moves allowed Israel to decimate much of Hezbollah’s senior leadership.

That increased Israel’s confidence and prompted its leaders to order a more decisive assault on the group. Troops invaded southern Lebanon and the air force killed Hezbollah’s secretary general, Hassan Nasrallah.

Israel then severely weakened Iran’s air defense systems and successfully repelled massive barrages of Iranian missiles, giving Israel greater confidence in its offensive and defensive abilities. More than a year after Oct. 7, Israeli leaders finally concluded that they had a rare window of opportunity to mount a decisive blow against Iran’s nuclear program.

Image An oil storage west of Tehran was hit by Israeli airstrikes on Sunday. Credit… Arash Khamooshi for The New York Times

Though Israel’s new approach has undercut Iran’s regional influence, it has done little to resolve Israel’s oldest and most intractable problem: the Israeli-Palestinian conflict.

In Gaza, Israel’s retaliation has led to widespread destruction and bloodshed, reinstating a fearsome sense of Israeli might and reducing Hamas’s threat for a generation.

But the conflict has provided no clear long-term trajectory for either Gaza or the wider Palestinian question. Mr. Netanyahu has consistently ignored opportunities to end the war, balking at the idea of either leaving Hamas’s remnants in charge or allowing other Palestinian groups to take over.

“Instead, we are left with only bad options,” said Tzipi Livni, a former Israeli foreign minister. “Either occupation or chaos, rather than a diplomatic process involving moderate regional and Palestinian stakeholders that could change the reality on the ground for both Palestinians and Israelis.”

A similarly aimless dynamic could yet emerge in Iran, analysts said, if the Israeli leadership fails to clearly define its goals there and set an exit strategy.

For now, Israeli officials hope the United States will join the attack and help Israel destroy Iran’s nuclear enrichment facilities. If the United States stays away, and if Iran refuses to stop the enrichment by choice, it is unclear whether Israel’s forceful new doctrine will achieve the kind of game-changing outcomes that many Israelis desire.

“One wonders whether effective military performance is matched by a sober political vision,” said Nimrod Novik, a former senior Israeli official and a fellow at Israel Policy Forum, a research group in New York. “Or, like in Gaza, we are left without an endgame. Time will tell.”

Johnatan Reiss and Gabby Sobelman contributed reporting.

It wasn’t long ago that supporters of burgeoning ties between Israel and Arab countries were promoting Dubai as the epicenter of regional harmony. Israeli influencers were moving to the dazzling Emirati city, which is just a ferry ride away from Iran. Investors were flitting between Dubai and Tel Aviv.

Since the war began last week with Israeli attacks on Iranian nuclear sites, the Emirates has waived all visa overstay fees for Iranians stranded in the country. On Tuesday, the Emirati ruler, Sheikh Mohammed bin Zayed, called the Iranian president to express “solidarity with Iran and its people during these challenging times.”

That reflects a sharp turn of events over the last five years, as Gulf governments that were once warming to Israel — seen as a potential ally in their battle to contain Iran — have decided that courting Iran with diplomacy is more pragmatic. And as the war in Gaza continues with no end in sight, spreading anger and despair and fanning the flames of unresolved conflicts across the region, some Gulf officials have come to view Israel as a major destabilizing force in the Middle East.

Residents of Dubai, the largest city in the United Arab Emirates, are now watching in dread as a regional war arrives at their doorstep, with missiles flying between Israel and Iran. As President Trump mulls entering the fray on the side of Israel, the fear of Iranian retaliation on American military assets in their country looms in the background.