Reuters: Kurdish forces backed by U.S.-led air strikes are pressing an attack on Islamic State in northeastern Syria that has killed at least 170 members of the jihadist group this week, a Kurdish official and a monitoring group said on Wednesday.

The official said Kurdish YPG fighters and allied militia have encircled Islamic State militants in a dozen villages near the town of Tel Tamr in Hasaka province. The region is important in the battle against Islamic State because it borders land controlled by the jihadists in Iraq.

The Kurdish YPG appear to be trying to drive Islamic State from a stronghold in the mountainous Jabal Abdul Aziz area to the southwest of Tel Tamr, said Rami Abdulrahman, who runs the Syrian Observatory for Human Rights monitoring group.