Iraqi troops backed by Shiite militias recaptured key areas of Beiji, a key refinery town, from the Islamic State militants Sunday, a general said.

Brig. Gen. Nassir al-Fartousi, commander of the Interior Ministry’s Quick Reaction Forces, told state TV that the Iraqi flag was raised on a local government building in Beiji and that troops were advancing toward other areas. He did not elaborate further.

Beiji is about 155 miles north of Baghdad. The town fell to the militants during its blitz across northern Iraq about a year ago, but parts of the town and nearby refinery have since been retaken by government forces. The town is strategically significant as it lies on the road to ISIS-held Mosul, the second largest city in the country.

Iraqi and Kurdish forces have managed to roll back the terror group in many parts of the country with help of U.S.-led airstrikes, and recaptured Tikirt in April. However, last month’s capture of Ramadi by ISIS has been the most significant advance in Iraq since last year.

The Islamic State has declared an Islamic caliphate in the territories it controls in Syria and Iraq, and has used oil facilities and smuggling to finance much of its operations.

The Associated Press contributed to this report