The Islamic State of Iraq and al-Sham (ISIS) has abducted at least 90 Assyrian Christians, including women and children, after overrunning a number of small villages in northeastern Syria, two activist groups said on Tuesday.The Britain-based Syrian Observatory for Human Rights, one of the activist groups, put the number of Assyrians held by ISIS at 90. The Observatory relies on a network of activists inside Syria.The group's fighters, who have targeted religious and ethnic minorities in Syria and Iraq since ISIS's increase in power, swept through the villages along the banks of Khabur River in Hassakeh province. The area is predominantly inhabited by Assyrians, who are an indigenous Christian people who trace their roots back to the ancient Mesopotamians.According to the activists, some Assyrians managed to escape from ISIS to the largely Kurdish-controlled city of Hassakeh.The fighting around Tal Tamr, the town which was most affected by the abduction, has coincided with heavy clashes between Kurdish militia and ISIS militants. Kurdish fighters from YPG launched an offensive over the weekend and seized some 20 villages from the extremists, backed by U.S.-led air strikes and Iraqi peshmerga.Hassakeh province is strategically important in the fight against ISIS because it borders both Turkey and ISIS controlled areas in Iraq.