This photograph shows a part of the Burgenstock luxury hotel complex above Lake Lucerne, where talks following up on a deal to end the Middle East conflict were scheduled to begin. AFP
The signing of the accord this week was intended to end the conflict in Iran, reopen the Strait of Hormuz and begin a 60-day period for talks on wider issues, including lifting the sanctions on Iran and Tehran's nuclear programme.
"The planned talks between the US, Iran, Qatar and Pakistan have been postponed," the Swiss foreign ministry said in a message to AFP.
"Switzerland remains ready to facilitate these talks. The relevant preparatory work at Burgenstock is continuing," it added, without providing a new date for the talks.
It followed the announcement late Thursday from the White House that Vance's trip was cancelled, with a spokesperson saying the "logistics of these negotiations have never been simple or predictable."
"We look forward to beginning technical talks as soon as possible."
In Iran, the Tasnim agency had said "nothing has been confirmed" about the Iranian delegation's trip to Switzerland.
The agreement has been signed separately by US President Donald Trump and his Iranian counterpart Masoud Pezeshkian.
Iran's supreme leader Ayatollah Mojtaba Khamenei said Thursday that he had approved the accord, despite reservations, even as the United States lifted a blockade of Iranian ports.
Mojtaba Khamenei, who took over after his father and longstanding ruler Ali Khamenei was assassinated in an American-Israeli airstrike on the first day of the war on 28 February, said in a written statement that he held a "different view" on the deal, without elaborating.
"But I issued my permission due to the commitment" made by officials including Pezeshkian to "protect the rights of the Iranian nation."
"Face-to-face negotiations" with the United States will be held in the future, but that does not "mean accepting the enemy's point of view," he added.
On Friday, Iran's chief negotiator Mohammad Bagher Ghalibaf warned that Tehran would give a "decisive" response if the agreement was breached.
The deal between Washington and Tehran was explicit that all hostilities between the US-Israel and Iran would end, including in Lebanon between Tel Aviv and Hezbollah.
However, overnight on Thursday, the Israeli occupation army killed at least 18 Lebanese in strikes in south and east Lebanon in violation of the US-Iran agreement that was signed on Wednesday to end all hostilities, including in Lebanon between Tel Aviv and Hezbollah.
On Thursday, refusing to abide by the Washington-Tehran deal, Israeli Prime Minister Benjamin Netanyahu stated that Israel would maintain its strikes and occupation of the south of Lebanon.
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