Baghdad -- When Keis Isitfan headed home from work one recent night, he had reason to watch his back. As a laundry worker for the U.S. embassy inside Baghdad's green zone, he risked being attacked by insurgents targeting Iraqis who work for the U.S. But there was another source of anxiety: Isitfan, 27, is a Christian and, like others of his faith, is facing growing hostility from hard-line Islamic groups who accuse Christians of being sympathetic to the Western occupiers.

As Isitfan was driving home on Sept. 7, his worst fears came true. After he left the green zone, two cars pulled up alongside, and attackers inside opened fire. Four bullets hit Isitfan, who died on the street. His family, convinced Isitfan was killed for his faith, plans to flee the country. "Christians in Iraq are weak," says his sister Layla, a translator for the U.S. embassy. "All they can do is leave here, like we will do."

Between 10,000 and 30,000 of Iraq's 800,000 Christians have fled the country since the fall of Saddam Hussein's regime, according to Christian groups in Baghdad. Although Christians make up only about 3% of Iraq's 25 million people, the U.N. High Commissioner for Refugees has said they account for about 20% of the refugees fleeing Iraq for Syria. They are escaping a climate of violence and a surging Islamic radicalism that have made the practice of their faith a deadly enterprise.

The worst moment came on Aug. 1 when Islamic insurgents