Talks between U.S. and Iranian negotiators had been deadlocked over Iran’s nuclear program and control of the Strait of Hormuz, through which passes a significant portion of the world’s oil and natural gas supply. Despite a cease-fire that began on April 7, inflation and wholesale prices in the United States have risen sharply as the war’s ripple effects continued to take a toll on the economy.

Cast by Mr. Trump in part as an effort to encourage Iranians to topple their theocratic leadership, the conflict — the second time in less than a year that Mr. Trump directly involved the United States in attacks on Iran — became a regional war in February that resulted in thousands of deaths, mostly in Iran and Lebanon. Hundreds of thousands of people were forced from their homes, and the global economy has been badly rattled.

Here are some key moments in the war:

Feb. 28: The United States and Israel launched strikes across Iran, hitting a government compound in Tehran and military targets. The blasts killed Ayatollah Ali Khamenei, the nation’s supreme leader for almost 37 years, as well as other high-level military and intelligence leaders.

At least 175 people, most of them likely children, were killed in a strike on a girls’ elementary school in southern Iran, health officials and Iranian state media said. The strike was a targeting mistake by the U.S. military, according to U.S. officials familiar with a military investigation.

Iran retaliated by firing missiles and drones at Israel and at U.S. military bases in the region, including in Qatar, Kuwait and the United Arab Emirates.

March 1: An Iranian drone attack killed six U.S. soldiers in Port Shuaiba, Kuwait, the first Americans to die in the war.

Hezbollah, an Iran-backed militant group, dragged Lebanon into the conflict, firing rockets toward Israel in retaliation for the killing of Iran’s supreme leader.

In a brief telephone interview with The New York Times, Mr. Trump offered several seemingly contradictory visions of how a new government could take shape in Iran and how the conflict would unfold. Asked how long the United States and Israel intended to sustain their assault on Iran, Mr. Trump said “four to five weeks.”

March 8: With several top Iranian leaders killed in airstrikes, Iran named Mojtaba Khamenei, a son of the slain supreme leader, as his father’s successor. Ayatollah Khamenei, 56, was appointed by a committee of senior Shiite clerics, signaling continuity and defiance after Mr. Trump called him an “unacceptable” choice.

March 11: Iran escalated its attacks in and around the Strait of Hormuz, striking at least three ships, according to a British maritime agency. Iran claimed responsibility for one assault on a bulk carrier from Thailand. The attacks sent oil prices surging and the Trump administration scrambling to pacify global markets.

March 12: Mojtaba Khamenei issued his first written statement as supreme leader, directing the military to continue choking off the Strait of Hormuz.

Six American crew members died after a KC-135 military refueling aircraft crashed in Iraq, bringing the number of U.S. service members killed in the war to at least 13.

March 13: The U.S. military conducted a large bombing raid on Kharg Island, Iran’s main oil export hub. Mr. Trump said the raid had targeted military infrastructure but did not hit oil facilities on the island, which is responsible for about 90 percent of Iran’s oil exports.

March 17: The Israeli military killed two of Iran’s top leaders: Ali Larijani, the head of the country’s National Security Council, and Gholamreza Soleimani, the head of the Basij, a militia aligned with the Islamic Revolutionary Guards Corps. The deaths represented the biggest blows to Iran’s leadership since Feb. 28.

March 18: Iran and U.S. allies traded attacks on key energy infrastructure in the Gulf. Israel attacked Iran’s South Pars gas field, which accounts for about 70 to 75 percent of its natural gas production. Qatar, a U.S. ally, said Iran had struck its Ras Laffan Industrial City, which is the world’s largest liquefied natural gas export plant.

March 23: Mr. Trump said that the United States and Iran were discussing an end to the war. It was the first public indication of diplomatic talks since the war began.

March 27: An Iranian strike injured 12 U.S. troops in Saudi Arabia on the Prince Sultan Air Base, one of the most serious breaches of U.S. air defenses in the war.

April 3: Iran shot down a U.S. Air Force F-15E fighter jet carrying two crew members, one of whom was recovered safely that day. The risky search-and-rescue operation for the second airman lasted two days and took commandos deep inside Iran. The downing of the F-15E was the first time that a U.S. combat aircraft was shot down in the war.

April 7: Mr. Trump announced a two-week cease-fire with Iran. Iran’s National Security Council confirmed the agreement, casting it as a victory.

April 8: Israel launched its heaviest bombardment of Lebanon since the start of the fighting, with more than 100 airstrikes in the space of just 10 minutes targeting Hezbollah. Israel said the U.S.-Iran cease-fire did not include Lebanon. On the same day, Iran publicly released a 10-point framework for talks, which included some maximalist demands.

April 11: Vice President JD Vance traveled to Islamabad for peace talks with Iran, brokered by Pakistan. Mr. Trump’s special envoy, Steve Witkoff, and his son-in-law, Jared Kushner, joined him. The Iranian delegation, led by the speaker of Iran’s Parliament, Gen. Mohammad Bagher Ghalibaf, included top diplomats, top military brass and finance experts.

April 12: The talks ended with no agreement as the two sides failed to compromise on major points, including Iran’s uranium stockpile and reopening the Strait of Hormuz.

April 16: Israel and Hezbollah agreed to a 10-day cease-fire in Lebanon in a deal brokered by U.S. diplomats, removing a major stumbling block to the talks between Iran and the United States.

April 17: Iran and the United States released statements declaring the Strait of Hormuz open to commercial vessels, following the Lebanon cease-fire agreement. Less than 24 hours later, Iranian officials closed the waterway and maritime officials recorded two incidents of vessels being hit.

April 19: American Marines fired on and seized an Iranian cargo ship that tried to evade the U.S. naval blockade.

April 21: Mr. Trump announced that he was extending the cease-fire with Iran, hours before it was set to expire, saying he would give Tehran time to come up with a new proposal to end the war.

May 1: Mr. Trump rejected Iran’s latest proposal to end the war. On the same day, the president sent letters to Congress saying that hostilities with Iran “have terminated.” The letters argued that the War Powers Resolution of 1973, which requires a president to seek congressional authorization to continue military operations after 60 days, did not apply because of the cease-fire.

May 18: Mr. Trump said that he had authorized a new wave of attacks against Iran but that he was holding off to allow for more negotiations on a nuclear deal. It was not the first time the president had threatened to restart the war, only to pull back at the last minute.

May 23: Mr. Trump said he had spoken with several Middle Eastern leaders about a memorandum of understanding “pertaining to PEACE” with Iran. “Final aspects and details of the Deal are currently being discussed, and will be announced shortly,” Mr. Trump said in a post on Truth Social. There was no immediate confirmation from Iran or Israel. But three senior Iranian officials said Tehran had agreed to a proposal that would stop the fighting on all fronts, including in Lebanon; reopen the Strait of Hormuz without any tolls; and lift the U.S. naval blockade on Iran.