The watchdog Syrian Observatory for Human Rights has reported that as many as 90 people, including adult males and females as well as children, were seized during a number of raids near Tal Tamr.
Some of the Assyrians were able to escape and reached Hassakeh a city that is largely controlled by the Kurds. This comes as Kurdish fighters in Syria backed by air strikes from the U.S.-led coalition continue advancing into territory held by the IS.
The province of Hassakeh is important strategically in the battle against the Islamic State since it borders both Turkey and the areas that the militant group controls in Iraq.
Reports from activists said that fighters from IS entered a number of villages along the Khabur River bank sometime around dawn Monday morning.
The SOHR, a group based in the UK that monitors the civil war in Syria, said 90 or more Assyrians were captured with the most coming from Tal Sharmran village. Another rights group said the total taken was from 70 to 100.
The group said that 3,000 were able to escape and sought refuge in Qamishli and Hassakeh that were northeast of the area.
A woman who is Assyrian from the Tal Shanran village and lives in Beirut said that she could not make contact with family members. She added that telephone landlines were cut and mobile phones have been turned off.
The Syrian Observatory said that in Tal Tamr heavy clashes took place between Kurdish militia units and the Islamic State.
Monday, Kurdish officials said that militants from IS were forced back to 3 miles from Tal Hamis a small town in the east.
Christians constitute what is believed to be 10% of the 22 million people living in Syria prior to the uprising nearly four years ago against Bashar al-Assad’s government.
There are estimated to be just 40,000 Assyrians in Syria. They speak Syriac, which is the language of Christ, a type of Aramaic and are Nestorian Christians.