Before boarding his flight to Europe, Vance told reporters he hoped to "make progress on the nuclear issue, make progress on the Lebanon ceasefire issue. Those are the two big things that I think we're going to be focused on".Follow-up talks had been planned in Switzerland on Friday but were postponed at the last minute after Israel launched deadly strikes in Lebanon following the deaths of four of its soldiers in combat.Washington announced a renewed ceasefire there later Friday -- a condition of its preliminary agreement with Iran -- but Israeli troops clashed again with Hezbollah fighters on Saturday, with each side accusing the other of breaking the truce.Citing a US "breach of contract" and "the Zionist regime's continuous and relentless violation of the ceasefire in southern Lebanon", Iran's central military command said "the Strait of Hormuz will be closed to vessel traffic."Hormuz, a key conduit for oil and gas shipments, was blockaded by Iran for much of the war, sending shockwaves through global energy markets.Tehran had agreed to reopen it under the preliminary accord signed by President Donald Trump and his Iranian counterpart Masoud Pezeshkian, and shipping traffic had begun to recover.US Central Command said after Iran's announcement that safe passage through the international waterway had "remained intact" and that US forces were "present and vigilant".Trump later warned that Washington could impose its own tolls on Hormuz if negotiators failed to complete the deal.There would be no tolls "unless they are imposed by and for the United States of America", Trump wrote on Truth Social.Switzerland push