UK Foreign Secretary Liz Truss and her US counterpart Antony Blinken have called for the immediate release of their citizens being held in Iranian jails.
The pair spoke at the UN General Assembly on Monday, the first time they had met since Ms Truss was promoted last week during a reshuffle of the top positions in the UK government.
In a statement unlikely to mollify European ally France, the two envoys also reasserted their ambition to build a stronger economic and security alliance and cited the new agreement with Australia designed to confront Chinese ambitions in the Far East.
France and China have both strongly criticised the pact. France was furious that a contract to supply submarines to Australia was cancelled because of the new agreement and China warned the signatories against meddling in regional affairs.
“On Iran, they [Truss and Blinken] agreed on the need for an immediate release of all arbitrarily detained British and American nationals and on the need for Iran to return to negotiations on the Joint Comprehensive Plan of Action in Vienna,” said a Foreign Office representative.
“They welcomed the recently agreed Aukus partnership on security in the Indo-Pacific region.”
Ms Truss has told the families of British detainees in Iran that she would take up their cases with Tehran during the global gathering.
They include charity worker Nazanin Zaghari-Ratcliffe, who has served a five-year sentence on trumped-up security charges but could be returned to jail after she was convicted on further charges. She is currently on bail.
Ms Truss also spoke with the wife of Anoosheh Ashoori, 67, a retired engineer who is serving a 10-year jail sentence on charges of spying for Israel’s Mossad intelligence agency. These charges have been dismissed as fabricated by his family and the UK government.
Ms Truss had also been due to meet her Iranian counterpart, Hossein Amir-Abdollahian, to discuss the detained Britons. The meeting has been delayed until Wednesday owing to travel problems for the Iranian delegation.