Concern is being raised for a Christian head teacher who's been arrested in Syria after being accused of apostasy.
Religious freedom group Christian Solidarity Worldwide says Radwan Muhammad, who converted from Islam, was taken by an Islamist group linked to the Muslim Brotherhood last month.
He was targeted at his home in Afrin after he refused to hand over his school building to the group so they could turn it into an Islamic school.
It's reported he told them: "I will hand you the building in one case only - if Jesus Christ comes down to earth again."
Apostasy is seen as a crime punishable by death by some hardline Muslims.
Radwan's friend, Pastor Nihad Hassan, who leads a Kurdish church in Beirut, Lebanon, and who is originally from Afrin himself, told CSW: "We are extremely worried about Radwan's life and wellbeing, he is being held at [Failaq Al-Sham's] Headquarters in Afrin and they may execute him.
"Those Islamist groups and their Turkish masters are walking in the footsteps of IS. In fact, many of their fighters are former IS and al Qaeda members."
The city of Afrin was captured by the Turkish army in 2018 with the help of Syrian Islamist groups. Amnesty International reports that since then "Afrin residents [have been] detained and tortured, with houses and businesses looted and confiscated, and schools destroyed or taken over."
CSW's chief executive Mervyn Thomas said: "We are deeply concerned for Mr Muhammad's welfare and we urge his abductors to release him immediately and without condition.
"We also urge the Turkish authorities to intervene by restraining the various Islamist Militia groups functioning under its command, and to immediately bring to an end all forms of violence and human rights abuses in the areas they control.
"We call on the international community to press Turkey to comply with international human rights and humanitarian law, and to cease all forms of persecution of religious minorities in Afrin and the surrounding area."