U.S. Vice President Vance said technical talks will continue and he will return to the United States shortly.

International oil prices opened higher on Monday after Trump warned he would strike Iran if Hezbollah continues to attack Israel, a move that raised doubts over progress in talks between Washington and Tehran. WTI crude rose as much as 1.7%. The warning came days after Trump signed a memorandum last week launching a 60‑day negotiation window; high‑level talks began at the Bürgenstock resort in Switzerland. Iran said it had again closed the Strait of Hormuz, but millions of barrels continued to transit the waterway over the weekend.

CNN reported on the 21st that U.S.-Iran talks are continuing in Switzerland and the U.S. delegation expects to work through the night. A senior U.S. diplomat said Iranian negotiators remain on site and U.S. negotiators, including Vice President Vance, have continued meetings with Iranian counterparts. Earlier the same day Iran paused negotiations to protest President Trump’s threatening remarks.