An Iranian negotiating team arrived in Switzerland on Saturday for talks with American officials, according to Iranian state media, and Vice President JD Vance is traveling to join them, with both sides aiming to flesh out the preliminary deal to end the war in Iran.

Pakistan, which has served as an intermediary in the peace effort, said on Saturday that “technical talks” would kick off on Sunday in Switzerland, including officials from Washington and Tehran, as well as Pakistani and Qatari mediators.

It was not clear if the talks would be face-to-face discussions, as in the last round in Islamabad, Pakistan, where both sides failed to reach an agreement after 21 hours of negotiating.

Before departing from Joint Base Andrews on Saturday, Mr. Vance told reporters that he would be in Switzerland for peace talks “for a day or two.” Earlier, he told Fox News that President Trump’s envoys, Steve Witkoff and Jared Kushner, were already in Switzerland ready to negotiate.

Iranian state media reported on Saturday that Tehran’s delegation was led by Gen. Mohammad Bagher Ghalibaf, Tehran’s lead negotiator in past talks and the speaker of Iran’s parliament. He is joined by Iran’s foreign minister, Abbas Araghchi, and Esmail Baghaei, the foreign ministry’s spokesman, among other officials, state media said.

The discussions come at a delicate time. The next phase of U.S.-Iranian talks was scheduled to start on Friday, but it was postponed after continued clashes between Israel and the Iran-backed militant group Hezbollah in Lebanon. Tehran said the Israeli strikes violated the memorandum of understanding, and Iran’s military went further on Saturday, claiming to close the Strait of Hormuz in response.

There are many other thorny questions that could be discussed during negotiations. President Trump’s interim agreement with Iran punted the future of Iran’s nuclear program to future talks, did not address Iran’s missile program and failed to resolve whether the Strait of Hormuz, the crucial maritime trade route off southern Iran, would remain open for free passage.

But Mr. Baghaei told state media on Saturday that the trip was intended to “follow up on the implementation of the other side’s commitments,” and warned that “negotiations on a final agreement” would begin only when Iran believes the United States is upholding the deal.

Tehran has accused the United States of reneging on commitments in the agreement by failing to rein in hostilities between Israel and Hezbollah, which exchanged fire again on Saturday, despite the announcement of a cease-fire in Lebanon on Friday. The U.S.-Iranian agreement calls for a cease-fire on all fronts, including Lebanon, but neither Israel nor Hezbollah have signed onto the pact.

Mr. Vance told reporters before departing on Saturday that he hoped negotiators would “make progress on the nuclear issue” and the “Lebanon cease-fire issue,” adding that he was “sure the Iranians are going to have issues they’d like to discuss as well.”

Sanam Mahoozi and Zolan Kanno-Youngs contributed reporting.