In this photo taken June 23, 2014, fighters from the Islamic State group parade in a commandeered Iraqi security forces armored vehicle down a main road at the northern city of Mosul, Iraq. Islamic State militants have abducted at least 70 Assyrian Christians, including women and children, after overrunning a string of villages in northeastern Syria, two activist groups said. (Uncredited/AP)

— The Islamic State has captured at least 70 Assyrian Christians in eastern Syria — including many women and children — in one of the militant group’s largest abductions targeting religious minorities, watchdog groups said Tuesday.

The Islamic State said it was holding “tens of crusaders” — a term it often uses to describe Christians — but other details were not clear.

The incident represents another blow to the Middle East’s besieged Christian communities, which have dwindled dramatically in recent years because of attacks by Islamist militants and others.

It also is the latest onslaught against religious minorities by the Islamic State, whose previous targets have included Yazidis in northern Iraq, who were taken captive and killed in much larger numbers last year.

The Assyrian captives could become bargaining chips as the Islamic State seeks to hold strategic ground linking its territory in Syria and Iraq. Some members of the embattled Assyrian Christian community — a group dating to biblical times — have taken up arms against the Islamic State.

Scores of hostages, including Westerners, have been killed by the Islamic State since 2014.

[Read: The Islamic State is failing at being a state]

But the Islamic State also has wreaked quick vengeance on those who fall into its hands. A video released this month showed the beheadings of 20 Egyptian Coptic Christians and a Ghanaian Christian held hostage in Libya by a branch of the Islamic State.

Syria’s oil-rich eastern region has been a key battleground in the fight against the militant group, which has faced repeated airstrikes from a U.S.-led international coalition. But the abductions, reportedly carried out during raids on villages, suggest some advances or retrenching by the extremists.

[View: The atrocities of the Islamic State]

As many as 90 people from the Assyrian Christian community were taken from villages in Syria’s northeastern province of ­Hasakah, according to the Syrian Observatory for Human Rights, a Britain-based group that monitors the civil war.

Another group that chronicles abuses by the Islamic State posted on its Facebook account that 70 people were abducted from villages near the town of Tal Tamr, citing figures obtained by Assyrian activists.

Many of those reported kidnapped are women and children, according to the group, which is called ISIS “Daash” Violations in Syria. ISIS and ISIL are acronyms for the Islamic State, and the group is often referred to in Arabic as Daesh or Daash.

Iraqi forces appear set to drive Islamic State militants out of the town of al-Baghdadi, securing an area near a key airbase where U.S. Marines are training local forces. (Reuters)

The reason for the discrepancy in the number is unclear, but the abductions coincide with intense clashes about 60 miles to the east of Tal Tamr between the Islamic State and Syrian Kurdish fighters.

The fate of the captives is not known. The Islamic State uses a violent interpretation of Islam to justify atrocities against religious minorities and opponents.

[Read: The plight of Syria’s vulnerable Christian minority]

Last summer, the group abducted and killed thousands of Iraq’s Yazidis, another ancient minority whose beliefs are vehemently rejected by the militants.

Rights groups say some captured Yazidi women have been used as sex slaves by the militant group, which also has systematically pillaged churches and razed shrines revered by both Shiite and Sunni Muslims.

Last month, however, the Islamic State released more than 200 Yazidis, most of them elderly or ill, who reached safety in northern Iraq’s semiautonomous Kurdish region.

In Syria, the Islamic State crucified, beheaded and shot as many as 700 members of the Shaitat tribe over three days in August, according to activists and survivors. The Muslim tribesmen had attempted to rise up against the group, touching off what is perhaps the Islamic State’s biggest massacre to date.

In a post Tuesday on his Facebook page, Zana Omer, a journalist from Hasakah province, said Islamic State fighters began attacking Assyrian villages near Tal Tamr on Sunday.

Kurdish fighters loyal to the People’s Protection Units, or YPG, intervened to stop the attacks, he wrote, adding that the Kurds helped evacuate residents of Tal Tamr and created safe corridors for Assyrians in neighboring villages to flee to nearby cities.

Omer said more than 1,200 Assyrians have taken refuge in the city of Hasakah and the smaller town of Qamishli.

The Assyrian Church’s roots go back to the first century of the Christian era, and many members speak a modern version of Aramaic, thought to be the language of Jesus.

The collapse of the Ottoman Empire in 1923 forced many Assyrians and members of other ancient Christian sects in the Middle East to emigrate, with most settling in the West.

Murphy reported from Washington. Sam Alrefaie in Beirut contributed to this report.