WASHINGTON (AP) — The U.S. on Thursday lifted its blockade of Iran, and oil tankers began freely moving through the Strait of Hormuz after months of being unable to use the critical channel, as the tentative agreement to end the war took effect.

Meanwhile, Vice President JD Vance announced that he may postpone a trip to Switzerland that had been planned for Friday and included a ceremonial signing of the deal. The visit might have helped start talks on the next, potentially even more critical, round of negotiations between the two sides.

Hours later, Iranian Supreme Leader Ayatollah Mojtaba Khamenei endorsed direct negotiations with the U.S. in a statement read by state media. It was Khamenei's first reaction to the agreement.

"It is obvious that the face-to-face negotiations that will be held in the future will not mean accepting the enemy's opinion," he said.

The supreme leader has not been seen in public since he was wounded in a strike at the start of the war.