An opposition monitoring group and a Kurdish official say hundreds of Kurds are fleeing villages controlled by the Islamic state group in the northern Syrian province of Aleppo.

Sherfan Darwish, a spokesman for the U.S.-backed Syria Democratic Forces, said Saturday that as one family fled they were struck by an exploding mine that killed two family members and wounded the remaining three. He says that a 10-year-old girl was killed by IS sniper fire.

People were fleeing their homes after IS abducted about 900 Kurdish civilians in Aleppo province over the past three weeks, forcing the captives to build fortifications for the extremists in retaliation for a Kurdish-led assault on a nearby IS stronghold.

The Britain-based Syrian Observatory for Human Rights said dozens more Kurds have been abducted since Friday.