President Trump said on Friday that he believed Iran abandoned its nuclear ambitions after recent U.S. and Israeli attacks on its nuclear infrastructure, but warned that he “absolutely” would be willing to bomb the country again if it resumed enriching uranium to a concerning level.

“Time will tell,” Mr. Trump told reporters at the White House, “But I don’t believe that they’re going to go back into nuclear anytime soon.”

Mr. Trump said such an outcome was unlikely, describing Iran as exhausted from the damage it had suffered and eager to speak with the United States. “Iran wants to meet,” Mr. Trump said.

But in a Truth Social post on Friday, Mr. Trump lashed out at Iran’s supreme leader, Ayatollah Ali Khamenei, for claiming in remarks to his people that Iran had prevailed in its conflict against Israel and the United States.

Mr. Trump called Mr. Khamenei’s assertion “a lie” and said that he had spared the Iranian leader’s life. He said he “knew EXACTLY” where Mr. Khamenei was sheltered and chose not to attack him or allow Israel to kill him. “I SAVED HIM FROM A VERY UGLY AND IGNOMINIOUS DEATH,” Mr. Trump wrote.

Mr. Trump also said in the post that he had begun work in recent days “on the possible removal of sanctions, and other things” to help Iran “recover.”