At least 132 Islamic State fighters have been killed since Saturday, Feb 21 in fighting with Kurdish militia backed by U.S.-backed air strikes in the northeastern Syrian province of Hasaka, a group monitoring the conflict said, according to Reuters.

The Kurdish YPG forces which drove Islamic State from Kobani last month with the help of U.S.-led air strikes had seized 70 villages in the offensive, the Syrian Observatory for Human Rights reported overnight.

The northeastern corner of Syria is strategically important in the battle against Islamic State because it borders territory controlled by the group in Iraq.