Karamlis, Iraq — Iraq’s Christians have taken up arms and formed new militias in a desperate effort to defend their beleaguered communities from an onslaught by Islamic extremists.

In the five years since the Anglo-American invasion, murders and abductions have forced about half of the 800,000 Christians who once lived in Iraq to flee the country.

Checkpoints manned by civilians with heavy machine guns and rifles have received official backing in Christian villages on the Ninevah plain in northern Iraq, where their presence dates back to the missions of St. Thomas the Apostle.

Father Yusuf Yohannes combines the duties of parish priest with overseeing security from a converted post office in the village of Karamlis, 10 miles east of the local capital, Mosul. Informal patrols by his parishioners started last year but the effort is now a fully fledged operation, with 250 employees and official approval from the American army base in Mosul.

“We are facing the threat of wipeout,” he said. “I have not left this town in three years because of the danger. The situation here was like a bowl without a base for Christians, we were just tossed around. By establishing our own security we have the chance to stand steady again.”