Iran's Foreign Ministry has said negotiations are ongoing to secure a prisoner exchange between Tehran and Washington despite US denials of a deal.
The US has denied Iranian claims of an imminent prisoner swap days after jailed dual national Siamak Namazi appealed to President Joe Biden to bring him home from Tehran's Evin prison.
“As has been said many times, negotiations through intermediaries have continued and are ongoing,” said the ministry spokesman Naser Kanani.
An agreement on a prisoner exchange was signed last March, he said, but a final resolution was delayed by the US, who tied it to continuing talks to revive the now-defunct nuclear deal.
“We are ready for this to be done as a humanitarian issue,” said Mr Kanani.
“The onus lies with the US.
“If the American sides take a realistic approach, the prisoner exchange can be done.”
Iran has sought for decades to free Iranians held in the US prisons.
Washington has dismissed rumours of the exchange as a “cruel lie” which only adds to the suffering of families with loved ones behind bars.
Tehran itself has jailed dozens of foreign and dual nationals since the collapse of the nuclear deal, with relatives and human rights groups accusing authorities of using them as bargaining chips against the West.
Most are detained without charge or accused of espionage, including Mr Namazi, who was found guilty of spying in 2016 and handed a ten-year sentence.
Mr Namazi appealed directly to the president for help, speaking to CNN from Evin prison last week.
“I desperately need President [Joe] Biden to finally hear us out, to finally hear our cry for help and bring us home,” he said.
Belgium's constitutional court recently upheld a treaty with Iran which would also pave the way for a prisoner exchange, raising hopes for detained aid worker Olivier Vandecasteele.
The Belgian national has been held in solitary confinement for more than a year and was sentenced to more than 40 years in prison in January after he was found guilty of espionage — condemned as “fake charges” by Brussels.
Speaking on the nuclear deal, Iran has also said it will need “verifiable guarantees” from the US before another agreement — echoing previous demands for a complete lift on sanctions to return to a deal.
Tehran needs such guarantees “due to the history of the American government's non-compliance with its obligations,” said Mr Kanani.
Signatories to the 2015 nuclear deal have failed to revive the accord despite multiple rounds of talks in Vienna.
Iran has demanded a full lift on sanctions to return to the negotiating table, a condition the US is not willing to meet.
Iran is capable of making the material for a nuclear bomb in just 12 days, Washington warned earlier this month, saying Iran has made “remarkable” progress since the breakdown of the accord.