A Canadian-Iranian academic has been released from prison by Iranian authorities, Canadian Prime Minister Justin Trudeau has confirmed.
The release was given on "humanitarian grounds", Iranian state media report.
Homa Hoodfar, 65, was one of several dual nationals being held for alleged "acts against national security".
She was ill and is being returned to Canada via Oman, the official Islamic Republic News Agency reported, citing the foreign ministry.
Mr Trudeau said the federal government had been "engaged at the highest levels" with her case.
"Canadians are relieved that Dr Hoodfar has been released from jail and will soon be reunited with her family, friends and colleagues," he said.
Canada, which cut diplomatic ties with Iran in 2012, worked closely with officials from Oman, Italy and Switzerland to help secure the academic's release.
Those Iranian authorities which assisted "understand that cases like these impede more productive relations," Mr Trudeau said.
Iran does not recognise dual nationality, which prevents those detained from receiving consular assistance.
'Dabbling in feminism'
Three others - Iranian-British national Nazanin Zaghari-Ratcliffe, Lebanese-US permanent resident Nizar Zakka and Iranian-US national Siamak Namazi - were all formally indicted alongside Ms Hoodfar in July.
Mrs Zaghari-Ratcliffe, a charity worker, has been jailed for five years on secret charges, her husband said last month.
Mr Zakka, an information and communication technology consultant, was sentenced to 10 years on 19 September by a secret tribunal, his supporters say.
Ms Hoodfar, formerly a professor of anthropology at Montreal's Concordia University, was initially detained in March but then released.
Three months later, she was arrested again and transferred to Evin prison, notorious for its treatment of detainees.
Her family said she has been accused of "dabbling in feminism and security matters".
The recent arrests of dual nationals appear to be part of a campaign by hardliners in Iran, BBC World Service Middle East Editor Sebastian Usher says.