SINJAR, Iraq — Iraqi Kurdish militias battling to take back Sinjar from Islamic State militants raised a Kurdish flag in the center of town and a top official said it was liberated today, though U.S. and Kurdish military officials urged caution in declaring victory in a major offensive to retake the strategic community.

The Kurdish forces encountered little resistance, at least initially, suggesting many of the IS fighters may have pulled back in anticipation of today’s advance. It was also possible they could be biding their time before striking back.

Kurdish militia fighters known as peshmerga launched a major offensive to retake Sinjar and succeeded in cutting a key nearby highway Thursday. U.S.-led coalition airstrikes supported the offensive, dubbed Operation Free Sinjar.

The town has been under the control of the Islamic State group for more than a year. The town was overrun by the extremists as they rampaged across Iraq in August 2014, leading to the killing, enslavement and flight of thousands of people from the minority Yazidi community.

“We promised, we have liberated Sinjar,” Massoud Barzani, the president of the semi-autonomous Kurdish region, told fighters in Sinjar. “It’s time for the Yazidi girls to raise their heads up. Revenge has been taken for them.”

“Sinjar is very important because it’s become a symbol of injustice against the Kurdish people,” he added.

Peshmerga Maj. Ghazi Ali, who oversees one of the units involved in the offensive, said thousands of Kurdish fighters entered the town from three directions this morning. Associated Press journalists saw them raise a flag over a building in the center of the city.

They encountered minimal resistance during the push, Ali said.

“No one was fighting back. They placed some IEDs and had some snipers in position, but there were no clashes,” he said, using the abbreviation for improvised explosive devices, a military term for homemade roadside bombs.