Iranian state TV has claimed Britain will pay a £400 million debt to Tehran in a move that could pave the way for the release of Nazanin Zaghari-Ratcliffe.
But there was no immediate acknowledgement from the UK Government on Sunday that a deal had been struck over the long-running dispute cited as a reason for her detention.
Quoting an anonymous official, a state broadcaster said deals had been reached with both Britain and the US in order to release prisoners with Western links held in Iran.
It was said the UK had agreed to pay the £400 million debt over the non-delivery of tanks dating back to the 1970s.
However, UK officials have downplayed the prospect of Nazanin Zaghari-Ratcliffe's imminent release.
The UK Foreign Office said "legal discussions are ongoing".
It was being said that the UK Government's position had not changed over the weekend and that Iran has made the claim before without the British-Iranian charity worker having been released.
Her husband, Richard Ratcliffe, who has campaigned for her release after her detention in 2016, told the PA news agency: "We've heard nothing."
"It's probably a good sign that it's being signalled, just as last week's sentence was a bad sign.
"But it feels part of the negotiations rather than the end of them."
The US was also said to have agreed a prisoner swap in exchange for the release of $7 billion of frozen Iranian funds.
However, a senior White House official has denied the reports from Tehran that an agreement had been reached.
"I can tell you, unfortunately, that report is untrue," White House chief of staff Ron Klain said on CBS's "Face the Nation".
"There is no agreement to release these four Americans. We're working very hard to get them released. So far there is no agreement to bring these four Americans home."
Additional reporting: AFP
