British Prime Minister Boris Johnson has called on Iran to release British-Iranians held in its prisons, including Nazanin Zaghari-Ratcliffe, who has been the subject of a high-profile human rights campaign.
In a phone call with Iran's President Hassan Rouhani, the prime minister said Ms Zaghari-Ratcliffe, who is understood to have completed her original sentence last Sunday, must be allowed to return home to her family.
Mr Johnson also pointed to similar cases of other jailed British-Iranians and urged Iran to adhere to the nuclear deal it has signed.
"The prime minister raised the case of Nazanin Zaghari-Ratcliffe and other British-Iranian dual nationals detained in Iran and demanded their immediate release," a statement from Mr Johnson's office said.
"He said that while the removal of Nazanin Zaghari-Ratcliffe's ankle monitor was welcome, her continued confinement remains completely unacceptable and she must be allowed to return to her family in the UK."
Ms Zaghari-Ratcliffe, 43, was released from Evin Prison about one year ago to serve part of her sentence under house arrest with an ankle monitor.
She was accused of plotting to topple the Iranian government, but her trial was held in secret and the case against her has never been made public.
She had hoped to be freed and allowed to leave Iran when her sentence was completed last Sunday.
That hope was dashed when Iran said it wanted her to appear in court the following Sunday.
Her house arrest was arranged as part of a programme to temporarily release thousands of prisoners due to the coronavirus pandemic.
In his phone call with Mr Rouhani, Mr Johnson also called on Iran to help stop breaching the terms of the nuclear deal, which both countries signed along with the US, China, Russia and other nations.
"The prime minister also stressed that while the UK remains committed to making the Iran nuclear deal a success, Iran must stop all its nuclear activity that breaches the terms of the [deal] and come back into compliance.
He stressed the importance of Iran seizing the opportunity presented by the United States’ willingness to return to the deal if Iran comes back into compliance.
“The prime minister underlined the need for Iran to cease wider destabilising activity and be a positive force in the Gulf region.”