MOUNT SINJAR, Iraq >> With coalition warplanes circling overhead, Kurdish fighters pushed into the contested northern Iraqi town of Sinjar on Sunday, touching off heavy clashes with Islamic State militants who have controlled the area for months. 

The battle for Sinjar and the surrounding area has become the latest focus in the campaign to take back territory lost to the Islamic State during the militants’ summer blitz that captured much of northern and western Iraq. The militants also control a large chunk of neighboring Syria.

Last week Iraqi Kurdish peshmerga fighters launched the operation to retake Sinjar. They’ve managed to open up a passageway to Mount Sinjar, a mountain that overlooks the town. That push allowed some of the thousands of Yazidis trapped on the mountain since the town’s fall in August to evacuate.

Pershmerga fighters said they advanced into Sinjar itself Sunday. Loud explosions and intense gunbattles could be heard from inside the town as U.S.-led coalition warplanes bombed Islamic State fighters from the sky. 

Earlier Sunday the president of the self-ruled northern Kurdish region, Masoud Bazani, toured Kurdish positions on Mount Sinjar, where he vowed to defeat the Islamic State. 

Meanwhile, Iraqi counterterrorism forces launched an offensive Saturday to retake the military airport near the town of Tal Afar, an Iraqi official said on condition of anonymity. 

Tal Afar is a mixed Shiite-Sunni city of some 200,000 located strategically near the Syrian border to the east of Sinjar. 

In Syria the U.S.-led coalition carried out at least a dozen airstrikes against IS-controlled towns in the northern province of Aleppo, the British-based Syrian Observatory for Human Rights said. The group monitors the conflict through a network of activists on the ground.