Four American prisoners in Iran were released Thursday into house arrest, family members said, raising hopes of a deal to allow them to leave the country.
The headway on the prisoners -- one of them detained for nearly eight years -- comes after quiet, exhaustive diplomacy between the adversaries that was believed to touch on ways to unfreeze $6 billion in Iranian funds held in South Korea.
Prisoners Siamak Namazi, Emad Sharqi and Morad Tahbaz and an unidentified fourth American were moved from Tehran's notorious Evin prison to an undisclosed house, a lawyer for the Namazi family said.
Sources said that a fifth American was also part of the discussions and had already been moved in recent weeks to house arrest.
"We are grateful that Siamak and the other Americans in Iran are out of Evin prison and will be under house arrest," said Babak Namazi, Siamak's brother.
"While this is a positive change, we will not rest until Siamak and others are back home; we continue to count the days until this can happen," he said in a statement.
A lawyer for the Namazi family, Jared Genser, also welcomed the step but cautioned that the Americans were not yet out.
"While I hope this will be the first step to their ultimate release, this is at best the beginning of the end and nothing more," he said.
All of the detained Americans are of Iranian descent. Iran does not recognise dual nationality and has had hostile relations with the United States since the 1979 Islamic Revolution toppled the pro-Western shah.
Namazi, a businessman, was arrested in October 2015. he was accused of spying on what his family calls laughable evidence such as past affiliations with US think tanks.
His father, former UNICEF official Baquer Namazi, was himself arrested as he went to help his son but was finally released last year as his health deteriorated.
Tahbaz, an Iranian-American who also holds British nationality, was arrested alongside other environmentalists in January 2018 and sentenced to 10 years in jail for "conspiring with America."
Sharqi is a venture capitalist who was also sentenced to 10 years on spying charges.