Experts say Iran is at the threshold of being able to enrich enough uranium to produce a nuclear weapon. The Islamic republic says its nuclear program is for peaceful purposes.

Iran’s U.N. mission said that “negotiations will never take place” if their aim is to dismantle Tehran’s “peaceful nuclear program.”

The apparently conflicting remarks may reflect a split among Iranian officials about whether to re-enter talks after Mr. Trump withdrew the United States from the nuclear deal struck with Tehran by his predecessor, Barack Obama.

Some moderate and reformist Iranian leaders, including President Masoud Pezeshkian, who took office last year, have said they want to begin discussions. Mr. Khamenei, however, has the final say and has said that Iran cannot trust the United States.

Mr. Trump’s offer comes as the strategic environment for Iran has deteriorated substantially.

Israel has severely weakened Tehran’s regional proxies, Hezbollah and Hamas, and destroyed almost all the air defense protecting Iran’s nuclear facilities. In December, a rebel coalition toppled Syria’s former authoritarian ruler, Bashar al-Assad, an ally of Tehran.