Updated

Kurdish and Christian militiamen battled Islamic State militants Wednesday in northeastern Syria, where the extremist group abducted at least 150 people from Assyrian Christian villages, according to activists.

Hassakeh province, which borders Turkey and Iraq, has become the latest battleground for the fight against the terror group Islamic State, also known as ISIS. It is predominantly Kurdish, but also has populations of Arabs and predominantly Assyrian Christians and Armenians.

A Syrian Christian group representing several NGOs inside and outside Syria told Reuters it had confirmed at least 150 people missing – including women and the elderly – after the villages were overrun by ISIS.

"We have verified at least 150 people who have been abducted from sources on the ground," said Bassam Ishak, President of the Syriac National Council of Syria.

ISIS has not confirmed the kidnappings, but online, supporters have posted pictures of the group’s fighters looking at maps and firing machine guns. The photos were purportedly taken in Tel Tamr, a town near where the abductions occurred, the Britain-based Syrian Observatory for Human Rights said.

In pre-dawn attacks Monday, Islamic State militants raided communities nestled along the Khabur River. Thousands of others fled to safer areas.

The fate of those kidnapped, almost all of them Assyrian Christians, remained unclear on Wednesday -- two days after they were seized. The 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 Assyrians are indigenous Christian people who trace their roots back to the ancient Mesopotamians.

"We are watching a living history and all that comprises 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 by American and Western powers to assist those Assyrian and Kurdish forces fighting the militants in Syria. The United States and coalition of regional partners are conducting a campaign of airstrikes against the group.

In its first comments on the subject, the Syrian state-run news agency SANA said around 90 civilians had been kidnapped by ISIS. It said that the militants burned people's homes and stole their properties, adding that those kidnapped were taken to Shaddadi city.

The Syrian Observatory for Human Rights and a Christian group called the Syriac Military Council said heavy clashes against ISIS militants in the area were continuing. The group, which is fighting alongside Kurds and Arab militiamen, said they were fighting to "push back the barbaric attacks against the freedom fighters."

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

The Associated Press contributed to this report.