Activists say number of Christians abducted by Islamic State group has risen to at least 220

Assyrians citizens hold placards during a sit-in for abducted Christians in Syria and Iraq, at a church in Sabtiyesh area east Beirut, Lebanon, Thursday, Feb. 26, 2015. Islamic State militants snatched more hostages from homes in northeastern Syria over the past three days, bringing the total number of Christians abducted to over 220 in the one the largest hostage-takings by the extremist group, activists said Thursday. Arabic on the placard, right, reads, "you can burn the churches but you cannot burn our faiths, and in this faith we will rebuild the churches." (AP Photo/Hussein Malla) (The Associated Press)

In this image made from video posted on a social media account affiliated with the Islamic State group on Thursday, Feb. 26, 2015, which has been verified and is consistent with other AP reporting, militants take sledgehammers to an ancient artifact in the Ninevah Museum in Mosul, Iraq. The extremist group has destroyed a number of shrines --including Muslim holy sites -- in order to eliminate what it views as heresy. The militants are also believed to have sold ancient artifacts on the black market in order to finance their bloody campaign across the region. (AP Photo via militant social media account) (The Associated Press)

An Iraqi Assyrian woman who fled from Mosul to Lebanon holds a placard depicting the map of Iraq and Syria, during a sit-in for abducted Christians in Syria and Iraq, at a church in Sabtiyesh area east Beirut, Lebanon, Thursday, Feb. 26, 2015. Islamic State militants snatched more hostages from homes in northeastern Syria over the past three days, bringing the total number of Christians abducted to over 220 in the one the largest hostage-takings by the extremist group, activists said Thursday. (AP Photo/Hussein Malla) (The Associated Press)

The number of Christians abducted by the Islamic State group in northeastern Syria has risen to 220, as militants have rounded up more hostages from a chain of villages along a strategic river in the past three days, activists said Thursday.

The Britain-based Syrian Observatory for Human Rights said the militants have picked up dozens more Christian Assyrians from 11 communities near the town of Tal Tamr in Hassakeh province.

The province, which borders Turkey and Iraq, has become the latest battleground in the fight against the Islamic State group in Syria. It is predominantly Kurdish but also has populations of Arabs and predominantly Christian Assyrians and Armenians.

IS began abducting the Assyrians on Monday, when militants attacked a cluster of villages along the Khabur River, sending thousands of people fleeing to safer areas.

Younan Talia, a senior official with the Assyrian Democratic Organization, said IS had raided 33 Assyrian villages, picking up as many as 300 people along the way. It was not possible to reconcile the numbers, and the fate of the hostages remained unclear.

State-run news agency SANA and an Assyrian activist group, the Assyrian Network for Human Rights in Syria, said the group had been moved to the IS-controlled city of Shaddadeh, a predominantly Arab town south of the city of Hassakeh. The Observatory, however, said they were still being held in nearby Mt. Abdulaziz.

The mass abduction added to fears among religious minorities in both Syria and Iraq, who have been repeatedly targeted by the Islamic State group. The extremists have declared a self-styled caliphate in the regions of both countries that are under their control, killing members of religious minorities, driving others from their homes, enslaving women and destroying houses of worship.

The U.N. Security Council on Wednesday evening "strongly condemned" the abduction and demanded the immediate release of others abducted by the Islamic State and similar groups.

The White House condemned the attacks, saying the international community is united in its resolve to "end ISIL's depravity."

The Assyrians are indigenous Christian people who trace their roots back to the ancient Mesopotamians.