BAGHDAD (UPI) -- The slaughter of dozens of Iraqi Christians held hostage in a Baghdad church seized by Islamist insurgents will accelerate the exodus of a Christian community that is one of the most ancient in the world. The flight of Iraq's dwindling Christian minority began several years ago when they became the target of Islamist militants like al-Qaida. Hundreds were killed or driven from their ancestral lands. The seizure of the Our Lady of Deliverance church in Baghdad, one of the city's main Roman Catholic places of worship, Sunday evening marked a sharp escalation in the campaign to drive out Iraq's Christians, caught between majority Shiite and minority Sunni Muslims. Some 120 people were taken hostage during Sunday services. On Monday, Iraqi anti-terrorist forces stormed the church, one of six bombed in August 2004. Maj. Gen. Hussein Ali Kamal, the deputy interior minister, said at least 52 people, including a priest, were killed in the final shootout. It wasn't clear whether the captives were killed by militants but Christian member of parliament Younadem Kana said, "What we know is that most of them were killed when the security forces started to storm the church." A statement posted on a militant Web site late Sunday, allegedly by the Islamic State in Iraq, claimed responsibility for seizing the church, which it called "the dirty den of idolatry." ISI is linked to al-Qaida in Iraq. Iraq's Christian communities -- the Assyrians and Chaldeans, along with smaller numbers of Armenians and others -- have practiced their faith since the days of Jesus Christ. The Assyrian Church of the East, for instance, was established in A.D. 33 by St. Thomas. The Assyrian Apostolic Church was founded a year later and can trace its origins to St. Peter. Times were tough under the tyrannical Saddam Hussein, a Sunni, but even in 1987 a census listed 1.4 million Christians in Iraq. Today, an estimated 700,000 remain, mainly on the Nineveh Plain north of Baghdad. As many as 600,000, and probably more, have fled since the insurgency erupted following the March 2003 U.S. invasion that toppled Saddam. But the trickle became a flood after Islamist extremists began systematically car-bombing churches in August 2004 and accusing Christians of collaborating with the Americans. But Iraq's Christians aren't the only ones on the run. Across the Middle East, and indeed in the wider Muslim world as far east as Indonesia, Christians are in retreat and often under fire. In the West Bank town of Bethlehem, reputed to be Jesus' birthplace, Christians once comprised 85 percent of the population. They're now 20 percent. Land belonging to Arab Christians, along with other Palestinians, is seized by Israel in the name of security, then handed over to Jewish settlers. Britain's liberal Guardian newspaper reported Thursday that the emigration of Christians from the Middle East "has accelerated in the last 15 years to the point where there is a real prospect of Christians disappearing from some parts of the cradle of Christianity." In Egypt, Iran, Turkey, Jordan and the Arab states in North African Christian communities are fighting for survival. In Lebanon, where Maronite Catholics were deemed the majority when the French left in 1943 and which was the only Arab nation to have a Christian head of state, Christians are leaving in droves as the Iranian-backed Shiites of Hezbollah grow in power and run a virtual state within a state. Christians lived in what is now called the Arab world before Islam took root in the seventh century. They have survived massacres and persecution over the centuries. But the demise of secular movements in the region and the growing influence of political Islam, as evidenced in its most violent form by al-Qaida, is driving out the last remnants. "The last prominent Christians -- Tariq Aziz, a Chaldean and Saddam's foreign minister for many years, and Hanan Ashrawi, Yasser Arafat's education minister -- have vanished from the political stage in the Middle East," Der Spiegel recently noted. Last week, Iraq's supreme court sentenced Aziz, Saddam's PR man who sought to justify his murderous excesses, to be hanged for "his role in the elimination of Islamic parties," the majority Shiites.