US Vice President JD Vance said Saturday he expects to travel to Switzerland in the coming days for talks with Iran, saying negotiations were going well — minutes before Tehran announced another closure of the Strait of Hormuz.

“I expect that I will leave some time the next couple of days, but, you know, it’s always a delicate coordination dance,” Vance told Fox News.

The vice president had unexpectedly postponed a planned trip two days earlier to discuss next steps on the US-Iran agreement aimed at ending the Middle East war.

Vance said US negotiators Jared Kushner and Steve Witkoff were already in Switzerland, handling “some of the technical elements” of the talks, and had reported that “things are going well.”

Pakistan said separately that technical talks on implementing the agreement would be held Sunday in Burgenstock, Switzerland, with Pakistani and Qatari mediators joining US and Iranian representatives.

Iranian state media said an Iranian negotiating team had left for Switzerland, after quoting foreign ministry spokesman Esmaeil Baqaei as warning that the agreement was “in trouble.”

The warning came as Iran said it was again closing the Strait of Hormuz, one of the world’s most important oil and gas shipping lanes, over renewed Israeli attacks in Lebanon.

Tehran accused Washington of a “breach of contract” and Israel of violating a ceasefire in southern Lebanon, saying the strait would be closed to vessel traffic.

Iran had blockaded Hormuz for much of the war, sending shockwaves through global energy markets, but had agreed to reopen it under the preliminary deal with Washington.

The US-Iran agreement was meant to halt the wider regional conflict on all fronts, including Lebanon, where Israel and Iran-backed Hezbollah have continued to trade fire despite a renewed ceasefire announced on Friday by Washington.

The Switzerland talks are intended to open a two-month negotiating period on unresolved issues, including Iran’s nuclear programme.