LONDON  - Britain’s foreign secretary said Sunday that Iran’s repeated sentencing of British-Iranian charity worker Nazanin Zaghari-Ratcliffe amounts to torture.

Speaking to the BBC’s The Andrew Marr Show, Dominic Raab accused Tehran of using her as leverage to gain concessions from the UK and said Iran has an obligation to release her immediately without any conditions.

"Nazanin is held unlawfully, in my view, as a matter of international law. I think she's being treated in the most abusive, tortuous way. I think it amounts to torture the way she's being treated," he said.

“It is clear that she is subjected to a cat-and-mouse game that the Iranians, or certainly part of the Iranian system, engage with and they try and use her for leverage on the UK."

Tehran is accused of using the aid worker as a bargaining chip in a dispute with London over decades-old unpaid debt owed to Iran as well as talks over the 2015 nuclear deal between Iran and world powers.

Zaghari-Ratcliffe was arrested in 2016, accused of spying for Western powers and spreading propaganda against the regime, charges she continues to deny.

She completed her five-year sentence in March 2021 when she was released and placed under house arrest. On April 26, however, Iran sentenced her to a further one-year jail term, accusing her of spreading propaganda against the regime.

Richard Ratcliffe, Nazanin's husband, welcomed the foreign minister’s remarks as they established a "rhetorical and legal red line."

"This has weight in international law. All states, including Iran, have an obligation to prohibit torture. You can't un-torture Nazanin, but the government can make sure this is not happening to others," he told the BBC.

- Claims of deal denied

According to media reports in the UK, Iranian state TV claimed that the British government has agreed to pay $552 million to free Nazanin.

"The release of Nazanin Zaghari-Ratcliffe in exchange for the UK's payment of its $552 million debt to Iran has also been finalized," an unnamed official reportedly said.

Tehran also claimed that it signed a deal with Washington on a prisoner swap in exchange for the release of $7 billion in frozen Iranian assets and funds.

However, the claims were immediately denied.

"Reports that a prisoner swap deal has been reached with Iran are not true. As we have said, we always raise the cases of Americans detained or missing in Iran. We will not stop until we are able to reunite them with their families," said a spokesperson for the State Department.

On behalf of the UK, a Foreign Office spokesman said: "We continue to explore options to resolve this 40-year-old case and will not comment further as legal discussions are ongoing."

Zaghari-Ratcliffe's local member of parliament Tulip Siddiq said the family had not confirmed the rumors.

"I am aware there are news reports circulating about the debt being paid to #FreeNazanin. I have spoken to her family and they have heard nothing confirming any of these rumours," she said on Twitter./aa