The Eritrean government has released on bail more than 20 prisoners who had been in detention for years because of their faith, sources have told the BBC.

The prisoners from Christian evangelical and Pentecostal denominations are among those being held in a prison outside the capital, Asmara.

In Eritrea only four religious groups are officially recognised - Christian Orthodox, Catholic Church, Lutheran Church and Sunni Islam.

Since 2002 all other religious groups have lacked the legal basis to practise their faiths publicly, including holding prayer meetings or weddings, according to the US Commission on International Religious Freedom.

US-based Hannibal Daniel, who campaigns for religious freedom, said people imprisoned for about 16 years were among those freed.

He said their conditional release could be linked to the coronavirus pandemic.

The Eritrean government has not officially commented on the reported release of the prisoners, but it has previously dismissed accusations of intolerance to religious freedom.

Campaigners advocating for religious freedom say three Jehovah Witnesses have been in prison in the country for more than 25 years.

The US State Department estimates that there are 1,200 to 3,000 prisoners of faith in Eritrea.