Trump Says Cease-Fire Has Started Between Iran and Israel

But the immediate consequences of the strike, at least for the direct conflict between the United States and Iran, appeared limited: President Trump said 13 of the 14 missiles Iran fired were downed and that there were no injuries or deaths among the roughly 10,000 American troops typically hosted there. A U.S. military spokesman said that the remaining missile had been allowed to land harmlessly. Satellite images captured by Planet Labs, a San Francisco-based Earth imaging company, showed that the base was nearly empty of aircraft ahead of the attack. Mr. Trump said the damage at the base was minimal.

Three Iranian officials said on Monday that their government had provided a warning about the strike to minimize potential casualties — allowing Iran a reprisal for the U.S. strikes on its nuclear sites while offering a way out of the direct conflict for both countries. Mr. Trump also said Iran had provided advance notice of the strike. “CONGRATULATIONS WORLD, IT’S TIME FOR PEACE!” he said on social media.

Similarly, Iran sent out an alert before retaliating in 2020 to the U.S. assassination of Iran’s most powerful security and intelligence commander, Maj. Gen. Qassim Suleimani, in a drone strike near Baghdad International Airport. It was a staggering blow for Iran and for Iranians, many of whom regarded him as a national hero. The country’s supreme leader, Ayatollah Ali Khamenei vowed a “forceful revenge.”

But days later, when Iran fired a series of ballistic missiles at American troops in Iraq, it gave the Iraqi government notice of the impending attack. The office of Iraq’s prime minister at the time, Adel Abdul Mahdi, said in a statement that it had received “an official verbal message” from Iran that its retaliation for the killing of General Suleimani had begun or would begin shortly and would be limited to sites where American troops were present.

The Pentagon said more than two dozen missiles were fired at two military bases in Iraq where American troops were stationed, Al-Asad and Erbil. Shortly after those strikes, both sides appeared to stand down. Iran’s foreign minister, Mohammad Javad Zarif, said on social media that Iran had “concluded proportionate measures in self-defense” and that his country did “not seek escalation or war, but will defend ourselves against any aggression.”

As in Iran’s attack on Al Udeid on Monday, Mr. Trump suggested in 2020 that initial assessments had found minimal damage and few casualties sustained by American forces. The Defense Department later said that more than 100 American service members had sustained traumatic brain injuries from the Iranian strikes on Al-Asad Air Base but that most had returned to duty.

Eric Schmitt and Farnaz Fassihi contributed reporting.

The announcement, made minutes after 6 p.m. Eastern time, caught even some of Mr. Trump’s own top administration officials by surprise. Israel has not yet confirmed the cease-fire, and within three hours of Mr. Trump’s announcement, there were fresh attacks from Israel against Iran, raising questions about whether all parties had agreed to it.

Mr. Trump had help in pressing for a cease-fire from Vice President JD Vance, Secretary of State Marco Rubio and Steve Witkoff, Mr. Trump’s special envoy, who had been leading the efforts over the last two months for a deal to curtail Iran’s nuclear program, the official said.

The three men worked through “direct and indirect” channels to reach the Iranians, the official said. Israel agreed to the cease-fire provided they aren’t subject to further attacks from Iran, the official said.

The official credited the U.S. military strikes on three Iranian nuclear enrichment sites on Saturday with setting the conditions for a cease-fire discussion.

The official did not say what conditions Iran may have agreed to, including whether it answered questions about the whereabouts of its stockpile of enriched uranium.

But Iran’s foreign minister, Abbas Araghchi, appeared to contradict Mr. Trump hours later, saying there was no agreement “as of now.” He also suggested that Iran would be willing to lay down arms if Israel stopped “its illegal aggression against the Iranian people” by 4 a.m. in Tehran.

An Israeli military spokesman declined to comment, and as that deadline approached, Israel was continuing to strike Iran with missiles in one of the most intense barrages of the war.

The three diplomats said that Mr. Trump had told Sheikh Tamim bin Hamad Al Thani, the emir of Qatar, that Israel had signed off on an American cease-fire proposal. They added that the president had asked that Qatar help bring Iran on board.

The Qatari prime minister, Sheikh Mohammed bin Abdulrahman Al Thani, then persuaded Iran to agree to the proposal in a call with the Iranian leadership, the diplomats said.

The exact details of what the diplomats said Israel and Iran agreed to remain unclear. Mr. Trump said on social media that the cease-fire would not take place until after the two countries “wound down” military missions in progress, a process he said would unfold in phases over a day.

On Monday evening, Iran attacked Al Udeid Air Base, a large U.S. military installation in Qatar, firing a fusillade of missiles at the site. The deal, if confirmed, would indicate that the wealthy Gulf emirate was simultaneously condemning Iran for its attack on Al Udeid and working to persuade the Islamic Republic to agree to a cease-fire.

Qatari officials have been key interlocutors in the indirect Gaza cease-fire talks between Israel and Hamas, and Qatar has long worked to present itself as capable of narrowing the gaps between warring parties.

Ronen Bergman contributed reporting.

U.S. commanders used the base to coordinate a wide variety of missions during the wars in Iraq and Afghanistan, as well as strikes against the Islamic State in Syria. The Air Force has deployed a wide variety of aircraft there, from advanced fighters and long-range bombers to drones, transport planes and in-flight refueling tankers.

It also became the central evacuation point for tens of thousands of Afghans and Americans who fled Afghanistan in 2021 when the U.S. military withdrew.

The Combined Air Operations Center at the base helps project U.S. air power across a vast region encompassing 21 countries, from Northeast Africa to Central and South Asia, according to the Air Force.

Qatar, which saw the United States as its main protector in the Middle East, finished building the base in 1996, hoping to encourage the deployment of the U.S. military there. Over the years, Qatar has spent at least $8 billion to develop the base, which its military also uses alongside the British Royal Air Force, as part of its efforts to build up its partnership with the United States.

The modernization and expansion of the base has allowed a number of key U.S. military commands to operate out of it. Along with the U.S. Central Command, the base also hosts command facilities for American special forces.

The base’s location was carefully guarded until 2013, when Chuck Hagel, then the defense secretary, lifted the veil of secrecy.

President Trump visited Al Udeid last month while on a four-day tour of Gulf States. There, in a rally-like atmosphere, he spoke about Qatar’s purchases of American military supplies and told several of his favorite stories, including one about his trip to Iraq during his first term.

“I have nothing else to do,” Mr. Trump told U.S. troops from a stage at the base, “so let’s have a little fun.”

They urged field offices to monitor their collection platforms and stay in close contact with the Defense Department, including the National Guard, “who may be targeted for retaliation” while “specific attention should be paid to” U.S. military facilities connected to the strikes in Iran.

In New York City, Mayor Eric Adams said that more police officers would be on duty around religious, cultural and diplomatic sites “out of an abundance of caution,” given the situation in the Middle East.

Iran, which the United States has designated as a state sponsor of terrorism, has long backed a network of militias across the Middle East in an attempt to extend its influence across the region and undermine Israel. Those militias include Hamas, Hezbollah and the Houthis, who control parts of Yemen.

Separately, the Department of Homeland Security issued a security bulletin stating that the “ongoing Iran conflict” had elevated security concerns in the country and adding that cyberattacks by pro-Iranian hackers were likely.

“The likelihood of violent extremists in the homeland independently mobilizing to violence in response to the conflict would likely increase if Iranian leadership issued a religious ruling calling for retaliatory violence against targets in the homeland,” the bulletin said.

It noted that “cyberactors affiliated with the Iranian government may conduct attacks against U.S. networks.”

Such advisories are typical after American forces take significant military action overseas, reflecting a worry by national security officials that people living in the United States may be angry or compelled to lash out. The relationship between Iran and the United States is particularly fraught in recent years, particularly given that U.S. officials have accused Iran of trying to assassinate American officials, as well as Iranian dissidents in the country.

In a conference call on Sunday, D.H.S. and F.B.I. officials cautioned state and local law enforcement officials of the possibility of threats to U.S. communities. During the call, the nonprofit organization Secure Community Network, which provides safety consulting and training for Jewish facilities across North America, said that the level of threats was very high.

“Iran would not strike in the U.S. unless a red line was crossed,” said Michael Masters, the group’s chief executive, according to a summary of the call. “That red line was assessed to be direct military engagement, especially targeting Iran’s nuclear facilities. That red line has now been crossed.”

The bulletin by the Department of Homeland Security said that the Iran-Israel war “could also motivate violent extremists and hate crime perpetrators seeking to attack targets perceived to be Jewish, pro-Israel, or linked to the US government or military in the homeland.”

Former F.B.I. officials said the bureau was well versed in these situations and would ask informants to find out if there were any new threats while scrutinizing existing cases, including possible surveillance of those being investigated.

In its email on Sunday, the F.B.I. said to prioritize tips potentially associated with Iran or its proxies.

Carlos Fernandez, a former senior F.B.I. agent in charge of New York’s counterterrorism division, said the agents had to take seriously the possibility of sleeper cells in the United States, especially since Iran has been accused of plotting to kill President Trump before the election and a human-rights activist in Brooklyn.

Indeed, the bureau has also uncovered members of Hezbollah, who trained in Lebanon but then moved to the United States, where they were eventually arrested in Michigan and New York and charged with terrorism.

“It’s very real,” he said. “It’s a legitimate concern.”