US Vice President JD Vance did not leave for Switzerland on Thursday to lead a new round of talks with Iran about its nuclear programme, AP reported Friday.
In a statement, the White House cited "difficult logistics" for negotiations behind the delay.
The White House said in a statement that plans for the technical talks have not been finalised, and the US delegation has been prepared to depart at the first available opportunity.
The development comes after the respective presidents of the two countries signed a 14-point interim agreement aimed at ending the nearly four-month long war that led to a global fuel crisis owing to the blockade of the crucial Strait of Hormuz.
The two countries have mutually decided to finalise the deal within 60 days.
Vance had been scheduled to travel to Switzerland for an official signing ceremony of the memorandum of understanding on Friday.
Earlier Thursday, Vance said he intended to travel to Switzerland for an in-person signing of the agreement, though he acknowledged the timing remained uncertain.
The US Vice President added that technical negotiations aimed at finalising the agreement were expected to begin this weekend and said he was “certainly planning” to lead the US negotiating team.
Meanwhile, the US Central Command lifted its blockade of the Strait of Hormuz, as per a statement made on X.
The 14-point agreement digitally signed by the US and Iran included the end of US-enforced naval blockade of the crucial strait.
Soon after the naval blockade was lifted, Iran's Supreme Leader Mojtaba Khamenei, as per a BBC report, said he had approved the deal with the US despite having a "different view", without elaborating.
Khamenei said President Trump had "out of desperation, used all kinds of leverage" to bring the deal about.