Iran said on Monday that the United States should provide guarantees that it will not abandon Tehran's 2015 nuclear deal with world powers again if talks to revive the agreement succeed.
Indirect talks between Iran and the United States, which stalled in June after the election of hardline Iranian President Ebrahim Raisi, are set to resume on November 29 in Vienna to find ways to reinstate the 2015 accord.
It has eroded since 2018 when then-US president Donald Trump withdrew from it and reimposed sanctions on Iran, prompting Tehran to breach mandated limits on uranium enrichment the following year.
"The US should show that it has the capability and will to provide guarantees that it will not abandon the deal again if the talks to revive the deal succeed," Foreign Ministry spokesman Saeed Khatibzadeh told a virtual news conference.
Echoing Iran's official stance, Khatibzadeh said Washington must lift all sanctions imposed on Tehran in a verifiable process and "recognise its fault in ditching the pact".
That ongoing stance is likely to cause concern in the US and with its European allies — France, Britain and Germany — who deem it unrealistic and want to resume June's talks where they left off without new demands.
One Western diplomat said if Tehran was genuinely continuing to demand a guarantee and full lifting of sanctions then it meant Iran was not serious about talks.
Khatibzadeh said Ali Bagheri Kani, who is Iran's top nuclear negotiator, will travel this week, as deputy foreign minister for political affairs, to the capitals of three European parties to the pact.
A French diplomatic source said Bagheri Kani would meet France's lead negotiator in Paris on Tuesday. A British Foreign Office spokesperson said Bagheri Kani would be in London on Thursday.
"We will urge Iran to take the opportunity to swiftly conclude the Joint Comprehensive Plan of Action deal on the table," the spokesperson said, adding that London would also press for the immediate release of detained British nationals.