Iranian church leader Yousef Nadarkhani has been released from prison and is to rejoin his family.
The decision comes as protests continue in the Islamic country against hijab-wearing, alongside a remarkable rise in Christian converts.
Commenting to Premier Christian News, Christian Solidarity Worldwide's Middle East Advocacy officer, Mena, called the decision "really good news". He said it was part of a national amnesty issued by Iran's Supreme Leader Ayatollah Khamenei to commemorate the anniversary of the 1979 Islamic Revolution.
"Pastor Nadarkhani is a prominent church leader. And he was spending a six-year sentence in the most notorious prison in Iran, where people are tortured to death. It's not the first time pastor Youssef went to prison, so he's been arrested many times before. But the news is totally unexpected."
Pastor Nadarkhani was one of four Christians arrested in Rasht on 13 May 2016 during a series of raids by Iranian security agents on Christian homes.
CSW's Mena explained: "Conversion in Iran is criminalised by law. It's illegal. According to the Sharia law, conversion or apostasy is punishable by death. Christianity is recognised in the Constitution, but only if you are an indigenous Christian. So those who convert from Islam to Christianity are prosecuted, and it's a serious, serious crime.
"It is illegal to practice to hold house church meetings, and to lead house church meetings, which is what Pastor Yusef and others were doing."
Since September, the Shia Iranian regime has been tested by mass protests which broke out after the death in custody of a young Kurdish woman, Mahsa Amini. She had been detained by morality police and accused of failing to wear her headscarf "properly".
According to Mena, Iran has a rapidly growing church which could be as big as 1 million Christians: "It is a revival, certainly, it is. A revival is happening in Iran. There is nothing the Iranian authorities can do to stop this process, they are aware of that. And that's why they target church leaders and Christian activists."
