'I expect Christians in Iraq will be gone'- CNN REPORTER

'I expect Christians in Iraq will be gone'

Still, such migrant workers are in the shadows and under threat of deportation, and more, if caught praying openly or communally. They haven't been in the Middle East long, and there's no guarantee any one of them will stay long, either.

That's in contrast to other Christian communities that have been in the Middle East for centuries.

Report: ISIS holding 260+ Syrian Christian hostages 01:39

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They're people like Assyrians, whose ancestors were part a cradle of modern civilization. They began converting to Christianity within years of Jesus' death and have kept the faith despite the growth of Islam in their homeland and, most shockingly, the Assyrian genocide of the 1910s and early 1920s.

Now those Assyrians in Iraq and Syria are under fire again.

Last August, ISIS militants overran Qaraqosh, a historic Assyrian community of about 50,000 people and Iraq's largest Christian city. And in recent days, the terrorist group stormed Assyrian villages in northeastern Syria, taking some 262 people hostage, said Assyrian Human Rights Network founder Osama Edward. Others fled for their lives, including about 600 taking refuge in St. Mary's Cathedral in al-Hasakah, Syria.

"We pray, we pray all the time," Romel David, who has 12 relatives thought to be among those kidnapped, told CNN affiliate KCRA. "What we've heard is it was like a sea of black uniforms marching through all the villages, burning down the churches, desecrating the crosses and wreaking havoc."

ISIS has targeted other Christians in the region as well, like those in Mosul, Iraq, who were told last July to convert to Islam, pay a fine or face "death by sword." Curry calls ISIS' actions against Christians "genocide." Yet it shouldn't obscure the fact that, even before this group's emergence, the number of Iraqi Christians was on the decline.

ISIS message to Christians: 'We're coming to get you' 03:00

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Some of that's due to a weak Iraqi central government and general instability. Christians might also be hurt by their historic affiliation with the Baath Party, once led by deposed Saddam Hussein (with the Syrian branch led by embattled President Bashar al-Assad). Another factor is the rise of militias and politicians who make Islam more central to their missions, to the exclusion of others.

Curry, from Open Doors USA, said Iraq had about 1.5 million Christians just over a decade ago. That number is now under 150,000, something that he attributes to family influences, government actions, communal pressure and targeted violence from militant groups.

"In 10 years from now," Jenkins added, "I expect Christians in Iraq will be gone."