MOUNT SINJAR, Iraq — Iraqi Kurdish forces forged ahead with their assault Monday on a militant-held town in northern Iraq, but encountered heavy resistance from Islamic State fighters whose snipers fired at the attackers and who used burning tires to create a smoke screen against coalition airstrikes.

The battle for the town of Sinjar has emerged as the latest fighting front in the campaign to chip away at the territory that the Islamic State captured in its summer blitz across northern and western Iraq.

Iraqi Kurdish peshmerga fighters launched their offensive on the town, located some 250 miles northwest of Baghdad, last week. In the opening days of the operation, the Kurds managed to reach thousands of Yazidis who were trapped on Mount Sinjar, which overlooks the town and sweeping desert plain below.

Peshmerga forces opened up a corridor to the mountain and are regularly bringing truckloads of aid and food to the area.

The clashes have moved to the edges of Sinjar itself, which the militants have held since August.

One Kurdish fighter, Bakil Elias, said the fighting has been fierce.

“They were using snipers and the peshmerga were responding with machine gun fire, missiles, and anti-aircraft guns,” he said before heading back to the front lines with his group of five other fighters.

At least two Kurds have been killed by snipers and 25 wounded in the latest fighting.

Kurdish forces also said the militants are burning tires and oil to create a smoke screen of thick dark clouds to obstruct airstrikes against their positions by the U.S-led coalition.

From a lookout atop Mount Sinjar on Monday, several pillars of thick smoke could be seen billowing over the town. The heavy thud of artillery and crackle of small arms fire echoed up the mountain.