A church leader in Northern Ireland has called for the world to stand together as Christians face "genocide" in Iraq.
His plea comes as the US launched an air strike against militants from the Islamic State (Isis) group in Iraq.
On Thursday President Barack Obama authorised air strikes but said he would not send US troops back in to the country.
Isis took control of the city of Mosul in June and earlier this week the fighters seized Iraq's biggest Christian town, Qaraqosh.
The town had previously been a safe haven for those fleeing Mosul but scenes reminiscent of Biblical times were played out as tens of thousands streamed out to seek shelter on a nearby mountain.
The Church of Ireland Bishop of Down and Dromore, Harold Miller, called for a united effort to help Christians in the war-torn country.
"It's really very important for the world at large to be supportive of Christians in Iraq," he said. "Christianity has been in Iraq for a very long time and what I have observed is that people are now being beheaded for their faith.
"The main Christian town has had most Christians expelled from it, like they did with Jewish people during the Nazi era.
"They are marking the houses of all the Christians with the letter 'N' because it comes from following Jesus of Nazareth. It's profoundly shocking."
The bishop added: "I suppose it also is a reminder to us of the most amazing thing of all that people of Christian faith will remain faithful to Christ no matter what happens."
The Reverend Andrew White, who is curate of St George's Church in the Iraqi capital, Baghdad, said Christians were facing genocide. Rev White was taught for four years by a Northern Ireland clergyman, Rev David Armstrong, who said he feels deeply concerned for the Anglican curate continuing his work in Iraq.
Rev White said: "Over the last few days we have been up here in the north of Iraq trying to ensure that we are providing holistically for all the people from whatever sector or religion. Despite us being Christian in orientation, we are there for everybody.
"Everybody is being massacred, slaughtered and what they are experiencing is worse than you could ever imagine."
He said: "The international community has got to wake up to the needs of people."
He added: "People's heads have been chopped off, they have been stuck on crosses, children have been killed and cut in half. It is just so awful."
Up to a quarter of Iraq's Christians are reported to be fleeing after Islamic militants seized the minority group's biggest town. The Islamic State (Isis) group captured Qaraqosh overnight after the withdrawal of Kurdish forces. President Barack Obama authorised air strikes against militants from Isis on Thursday, but said he would not put US forces back on the ground. Since June, Isis has been steadily gaining ground in northern Iraq.