Elon Musk, a close adviser to President-elect Donald J. Trump, met with Iran’s ambassador to the United Nations on Monday in New York in a session that two Iranian officials described as a discussion of how to defuse tensions between Iran and the United States.

The Iranians said the meeting between Mr. Musk and Ambassador Amir Saeid Iravani lasted more than an hour and was held at a secret location.The Iranians, who spoke on the condition of anonymity because they were not authorized to discuss policy publicly, described the meeting as “positive” and “good news.”

Asked about whether there was such a session, Steven Cheung, Mr. Trump’s communications director, said, “We do not comment on reports of private meetings that did or did not occur.” Mr. Musk did not respond to a request for comment.

Karoline Leavitt, the transition spokeswoman for the incoming Trump-Vance administration, said in a statement: “The American people re-elected President Trump because they trust him to lead our country and restore peace through strength around the world. When he returns to the White House, he will take the necessary action to do just that.”

Mr. Musk has emerged as the most powerful private citizen in the Trump transition, and has sat in on nearly every job interview. During a call last week with Ukraine’s president, Volodymyr Zelensky, the president-elect handed the phone to the billionaire. Mr. Musk has played a key role in providing communications capability to Ukraine in the war with Russia.

An early direct meeting between a senior Iranian official and Mr. Musk raises the possibility of a change in tone between Tehran and Washington under the Trump administration, despite a charged history between the president-elect and Iran. One of the Iranian officials said that it was Mr. Musk who had requested the meeting and that the ambassador picked the site.

During his first term Mr. Trump pulled the United States out of the 2015 nuclear accord between Iran and world powers, calling it “a horrible one-sided deal that should have never, ever been made,” and imposed tough economic sanctions on Iranian oil revenues and international banking transactions. He also ordered the assassination of a top Iranian general, Qassim Suleimani, in Iraq in 2020.

In response, Iran’s supreme leader banned any negotiations with the Trump administration and Iranian officials vowed to avenge Mr. Suleimani’s killing. Federal prosecutors said in a court filing last week that Iran had plotted to assassinate Mr. Trump before the election.

But in the wake of Mr. Trump’s election last week, Iran has been openly debating whether it can now reach a new and more lasting deal with the United States. Many members of President Masoud Pezeshkian’s new government favor negotiating, arguing that Mr. Trump likes to make deals and that there may be an opportunityto get the sanctions lifted.