Under the terms of the agreement, known as the “memorandum of understanding,” the United States is to begin dismantling its naval blockade of Iran immediately, while Iran is to clear the mines it scattered across the Strait of Hormuz and reopen the waterway to commercial shipping, the officials said.

Under the agreement, the roughly two-month-old cease-fire that the two sides reached in April would be extended for another 60 days to allow for talks on a final accord.

The two sides will begin tackling the nuclear issues in detail in a new round of negotiations. Those could begin as soon as Friday in Geneva, where Iran and American officials, including Vice President JD Vance, will also sign Sunday’s accord in person.

Iran affirmed in the agreement that it would never seek to build or procure a nuclear weapon, but the regime has made that promise many times previously, including in the deal signed with the United States under President Barack Obama in 2015.

Neither government has released the text of the agreement, but the terms seem a long way from the “unconditional surrender” that Mr. Trump had demanded early in the war, which began with U.S. and Israeli airstrikes on Feb. 28. In the end, the Iranians withstood a heavy assault from both nations, and endured the loss of their leadership. Yet while Iran’s economy and military industrial base were both severely damaged, the regime remained standing. Iran maintains a substantial stockpile of ballistic weapons and, at the same time, the United States has burned through its own munitions supplies to an alarming extent.

The political costs of the war to Mr. Trump also remain unsettled: Many supporters have expressed disappointment that a candidate who ran for president on the promise of no new wars in fact started one — and is apparently ending one inconclusively. Inflation, particularly energy costs, have weighed on consumers as midterm elections approach. Polls have found the war broadly unpopular, further diminishing the president’s already-low approval rating. Republicans running for office have been eager to put the conflict behind them.

The Trump administration hopes the next phase of technical talks will result in Iran’s committing to destroy its nuclear program and hand its near-bomb-grade enriched uranium over to the United States to be diluted and removed from the country. The Trump team also envisions a strict enforcement program, but the history of nuclear diplomacy with Iran suggests that these issues will not be easy or quick to resolve.