Iraqi air force backed the militia's push into the border town, the Popular Mobilization group announced on Sunday.

The victory over the self-styled "Islamic State" (IS) fighters was a "big and qualitative achievement" in the larger operation to retake the city of Mosul from the IS jihadis, said deputy chief of the Popular Mobilization Forces, Abu Mahdi al-Muhandis.

The border town is located west of Mosul, and its loss cuts a key IS supply lines connecting the city with Syria. Baghdad's troops launched the offensive to liberate Mosul eight months ago and uprooted the jihadi militia from several parts of the city. However, IS forces are still holding the western section of their last remaining urban stronghold in Iraq.

Iranian advisors active in Syria and Iraq

Despite the US backing, the anti-IS coalition was forced to slow down its efforts while facing car bombs and sniper fire in the densely populated areas of Mosul.

The retaking of Baaj comes several weeks after the Popular Mobilization Forces started their push to reclaim the area near the Syrian border. IS leader Abu Bakr al-Baghdadi is believed to be hiding in the region.

While the Shiite-dominated militia nominally answers to Baghdad, it is supported by the Shiite power Iran. Tehran provided training and military advisors to the Iraqi group, and also helped organize thousands of Shiite fighters from Iraq, Afghanistan, and Pakistan in Syria.

dj/sms (dpa, AP, AFP, Reuters)