President Trump said on Saturday that the United States was close to reaching an agreement with Iran toward ending the war and reopening the Strait of Hormuz.

Mr. Trump provided few details about the preliminary agreement, which he said was “largely negotiated.” It is unclear whether the latest negotiations will succeed in extending the current cease-fire and reach a more permanent peace, or break down over the sticking points that have kept the war unresolved for months.

In a post on Truth Social, Mr. Trump said he had spoken by phone with several Arab leaders about a memorandum of understanding “pertaining to PEACE.” He said the agreement was “subject to finalization” by the United States, Iran and other countries.

“Final aspects and details of the Deal are currently being discussed, and will be announced shortly,” he wrote.

There was no immediate confirmation from Iran or Israel. But three senior Iranian officials said Tehran had agreed to a memorandum of understanding that would stop the fighting on all fronts, including Lebanon; reopen the Strait of Hormuz without any tolls; and lift the U.S. naval blockade on Iran.

The officials, who spoke on condition of anonymity because they were not authorized to speak publicly, added that the fate of Iran’s nuclear program, which had been a major point of contention, would be negotiated within 30 to 60 days. It was not clear whether the proposal the Iranian officials said they had agreed to was the one Mr. Trump was referring to in his social media post.

Earlier Saturday, Esmail Baghaei, Iran’s Foreign Ministry spokesman, said Washington and Tehran were in the “final stage” of drafting a memorandum of understanding, adding that they “may be able to reach a mutually acceptable solution.”

Mr. Trump’s announcement followed a wave of last-ditch diplomatic efforts to stave off a return to full-scale war, with Pakistani and Qatari mediators traveling to Iran, and Mr. Trump’s call with Middle Eastern leaders. Mr. Trump also said he had spoken with Prime Minister Benjamin Netanyahu of Israel, whose country joined the initial attack in late February that launched the war.

The United States, Israel and Iran agreed to a cease-fire in early April after more than a month of war. The truce was intended to allow talks on Iran’s nuclear program and the reopening of the Strait of Hormuz, a crucial waterway for oil and gas shipping that Iran has effectively closed since the war’s early days, driving energy prices worldwide to soar.

Here’s what else we’re covering:

• Israeli reaction: Mr. Netanyahu has yet to comment on Mr. Trump’s announcement. The New York Times has reported that the Trump administration effectively cut Israel out of the negotiations with Iran, leaving Israeli officials struggling to get a clear picture. And it remains to be seen whether a potential agreement would indeed halt Israel’s ongoing clashes with the Iran-backed militant group Hezbollah in Lebanon, which rattled the broader cease-fire with Iran when Mr. Trump declared it back in April.

• Middle East reaction: Leaders from Arab and Muslim-majority countries told Mr. Trump by phone on Saturday that they support the latest proposal to end the Iran war and urged him to accept it, according to three Middle Eastern officials, who spoke on the condition of anonymity because they were not authorized to speak publicly.