Religious freedom charity Middle East Concern is calling on Christians around the world to pray for four men who are beginning prison sentences after converting from Islam.

Hossein Kadivar, Khalil Dehghanpour, Kamal Naamanian and Mohammed Vafadar have this week started their five year sentences at the notorious Evin Prison.

The men, who all belong to the Church of Iran, were arrested last year accused of "acting against national security".

While they appealed their convictions, the sentences were upheld on appeal in February.

Of the four men who presented themselves at Evin Prison earlier this week, three are married with families, while Mohammad is single. 

Middle East Concern reports that their friends have asked for prayer that: "God will comfort the families of all Christians in prison, providing for their needs and caring for the children in particular. 

"God will grant his peace to those who recently started serving their prison sentences and encourage them greatly and Iran will respect the freedom of its citizens to follow the faith of their own choosing and stop criminalising the activities of Christian converts as though they are acting against national security."