BEIRUT -- Islamic State of Iraq and Syria (ISIS) militants have seized more than 200 Assyrian Christians in raids on about 10 villages in northeast Syria this week, a monitoring group said Thursday.

The British-based Syrian Observatory for Human Rights, which relies on an extensive network of activists on the ground in Syria, said at least 220 Assyrians had been abducted by the group.

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

In pre-dawn attacks, ISIS on Monday attacked communities nestled along the river, seizing at least 70 people, including many women and children. Thousands of others fled to safer areas.

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The fate of that first group kidnapped, almost all of them Assyrian Christians, remained unclear Wednesday. Relatives of the group searched frantically for word on the fate of the loved ones, but none came.

"It's a tragedy ... It is true what they say: history repeats itself," said Younan Talia, a high ranking official with the Assyrian Democratic Organization who spoke to The Associated Press from Hassakeh.

He was referring to the 1933 massacre by Iraqi government forces of Assyrians in Simele, a town in northern Iraq, after which the community fled to the Khabur region, and massacres against Armenian and Assyrian Christians under the Ottoman empire.

State-run SANA news agency and the Assyrian Network for Human Rights in Syria said the hostages have been moved to the ISIS-controlled city of Shaddadeh, south of the city of Hassakeh. The United States and a coalition of regional partners are conducting a campaign of airstrikes against the group, and have on occasion struck Shaddadeh, a predominantly Arab town.

"In addition to its strategy of terrifying people, taking hostages to use as human shields to protect from coalition airstrikes is another of its goals," said Osama Edward, director of the Stockholm-based Assyrian Network for Human Rights in Syria.

The mass abduction added to fears among religious minorities in both Syria and Iraq, who have been repeatedly targeted by ISIS. During the group's bloody campaign in both countries, where it has declared a self-styled caliphate, minorities have been repeatedly targeted and killed, driven from their homes, had their women enslaved and places of worship destroyed.

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

The White House condemned the attacks, saying the international community is united in its resolve to "end ISIL's depravity," referring to the group by an alternate acronym.

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

Talia said ISIS militants had raided 33 Assyrian villages on Monday, picking up as many as 300 people along the way. Many were plucked from their beds at dawn. A man who refused to leave his home was set on fire along with his house.

He added that more than 700 families who fled Khabour region had arrived in Hassakeh, while 200 other families fled to Qamishli.

"We are watching a living history and all that comprises (it) disappear," wrote Mardean Isaac of A Demand for Action, an activist group that focuses on religious minorities in the Middle East.

He called for further airstrikes to assist those Assyrian and Kurdish forces fighting the militants in Syria.

ISIS also released a video on Thursday showing militants using sledgehammers to smash ancient artifacts in Iraq's northern city of Mosul, describing the relics as idols that must be removed.

The five-minute video shows a group of bearded men inside the Mosul Museum using hammers and drills to destroy several large statues, which are then shown chipped and in pieces. The video then shows a black-clad man at a nearby archaeological site inside Mosul, drilling through and destroying a winged-bull Assyrian protective deity that dates back to the 7th century B.C.

In its first comments on the subject, SANA said around 90 civilians had been kidnapped by the extremists. It said that the militants burned people's homes and stole their properties, adding that those kidnapped were taken to Shaddadeh.

Another activist group, based in ISIS defacto capital city of Raqqa, said Wednesday that the hostages had been brought there. The group, which calls itself "Raqqa is Being Slaughtered in Silence," said on their blog that ISIS fighters had brought the Assyrian hostages to the city, about 150 miles southwest of Hassakeh.

None of the claims regarding the whereabouts of the Assyrian Christian hostages could be independently verified.

It quoted the patriarch of the Greek Catholic church, Gregory III Laham, as saying that in addition to the abductions, the militants destroyed the historic church in Tal Hurmiz, one of the oldest in Syria.

"Does the world need additional proof to stand united effectively against this epidemic and this criminal, inhuman group," he asked.

Edward, who said his organization relied on observers on the ground in Syria, said two historic churches have been burned by the militants, one in Tal Hurmiz and the other in Qaber Shamiyeh.

Yunan Ruel Odishu, a priest from Tal Hurmiz currently in Dohuk, Iraq, said the Islamic State group issued a statement last month warning them to remove the cross from the village church, but the priest there didn't respond.

"In the last few days, they attacked all the villages. We think as a response to that," he said.

The Britain-based Syrian Observatory for Human Rights and a Christian group called the Syriac Military Council said heavy clashes against militants in the area were continuing. The group, which is fighting alongside Kurds and Arab militiamen, said three of its fighters were killed in Tal Hurmiz Tuesday.

"The Syriac Military Council and the Khabur Guards are determined to fight back ISIS, to regain the Assyrian villages and to release the Assyrian Christian hostages from ISIS," it said in a statement, using an alternate acronym for the Islamic State group.

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 extremists could also use the Assyrian captives to try to arrange a prisoner swap with the Kurdish militias it is battling in northeastern Syria.

Talia appealed for "anyone with a free conscience" to address the tragedy of the Assyrians.

"We have lost our homes, our property, everything. But the hardest thing we lost is our dignity," he said.