Islamic State militants in north-eastern Syria have abducted at least 90 Assyrian Christians, a monitor that tracks violence in the region said today.

According to the London-based Syrian Observatory for Human Rights (SOHR), IS jihadists undertook dawn raids in a number of villages inhabited by the ancient Christian minority near Tel Hmar, south of the Khabour river, on 23 February.

Sources told SOHR that they heard militants over wireless devices confirming that they had detained "56 crusaders" from the village of Tal Shamiram. Dozens of Assyrian people were also reportedly abducted from the village of Tal Hermez.

SOHR's network of sources also said that two people were executed by militants for "dealing with Kurds" in the nearby village of Ghibsh.

The reports have been confirmed by campaign group A Demand for Action (ADFA), which is working to protect and support Assyrians, Chaldeans and Syriacs in Iraq and Syria.

IS militants attacked the villages at around 5am on Monday, displacing an estimated 3,000 people, the group has confirmed. Those kidnapped were mostly women and children, while the men were taken to the Abd al-Aziz mountains. The women and children are now believed to be being kept in Tal Shamiram, guarded by IS militants who are demanding a prisoner exchange with Kurdish fighters. They have threatened to kill the captured men if the swap does not go through.

A journalist in Khabour told ADFA that a church had been burnt down in the village of Qabr Shamiye, and around 500 families have been forced to take refuge with relatives in cities such as Hassakah and Qamishli. Iraqi activist Steven Nabil tweeted that one of the oldest churches in Syria has also been destroyed in Tel Hurmiz, along with the Mar Bisho church in Tel Shamiran and the church in Tel Baloua.

ADFA says it has called the mobile phones of those taken hostage, but IS militants answered them and "told us that we should not call any longer since we cannot do anything about their situation".

The attack follows the murder of 21 Egyptian Coptic Christians by IS militants in Libya earlier this month.