Islamic State militants have abducted some 90 Christians, including women and children, after overrunning a string of villages in north-eastern Syria, activists and relatives said on Tuesday.
The militants struck before dawn, carrying out house-to-house raids in a cluster of villages nestled along the Khabur River in northeastern Syria. They abducted at least 90 Christians - many of them women and children - while thousands of others fled to safer areas.
The captives' fate is still unclear, and relatives said mobile phone services were cut off and land lines also were blocked, adding to the fear and uncertainty about their loved ones. Heavy fighting was reported in the area.
The United States has demanded that the Islamic State release the kidnapped Assyrian Christians.
State Department spokeswoman Jen Psaki condemned the attacks and said the militants must release all civilians they are currently holding.
"ISIL's latest targeting of a religious minority is only further testament to its brutal and inhumane treatment of all those who disagree with its divisive goals and toxic beliefs," she said, using an acronym for the group. "ISIL continues to exact its evil upon innocents of all faiths, and the majority of its victims have been Muslims."
The Islamic State group has a history of killing captives, including foreign journalists, Syrian soldiers, and Kurdish militiamen. Most recently, militants in Libya affiliated with the extremist group released a video showing the beheading of 21 Egyptian Christians.
The group's bloody campaign in Syria and Iraq, where it seeks to form a self-styled caliphate, has repeatedly targeted religious minorities since it took control of a third of both countries. The United States and coalition of regional partners are conducting a campaign of airstrikes against the group.
The militants struck near the town of Tal Tamr in Hassakeh province, an area dominated by Assyrian Christians. Most of the captives came from Tal Shamiram and some from Tal Hurmiz.
Nuri Kino, the head of a group called A Demand For Action, said between 70 and 100 Assyrians were taken captive. About 3,000 people fled and have sought refuge in the cities of Hassakeh and Qamishli, he said, adding that his activist group based its information on conversations with villagers who fled the attack and their relatives. His group focuses on religious minorities in the Middle East.
The Britain-based Syrian Observatory for Human Rights, which also reported the abductions, put the number of Christians held by the Islamic State group at 90. The Observatory relies on a network of activists inside Syria.
Both groups said that most of the captives come from Tal Shamiram, located some 85 km southwest of the provincial capital of Qamishli, and nearby Tal Hurmiz. At least four civilians, including a 17-year-old, were killed in clashes later Monday.
The extremists could use the Assyrian captives to try to arrange a prisoner swap with the Kurdish militias it is battling in northeastern Syria.
Last year, IS militants abducted more than 150 Kurdish boys and held them in a school in Aleppo province where they subjected to daily instruction on militant ideology for five months before releasing them in batches.
The group has also released Turkish truck drivers and diplomats after holding them for months. It was not known whether a prisoner deal was struck in those instances.