Iraqi Kurdish militia fighters fighting to take back Sinjar from Islamic State militants raised a Kurdish flag and fired off celebratory gunfire in the center of town Friday, November 13, though U.S. and Kurdish officials cautioned that it was too soon to declare victory in a major offensive to retake the strategic community, the Associated press reports.

The Kurdish forces encountered little resistance, at least initially, suggesting that many of the IS fighters may have pulled back in anticipation of Friday's advance. It was also possible that 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 on Thursday. U.S.-led coalition airstrikes supported the offensive, dubbed Operation Free Sinjar.

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

Col. Steven Warren, a spokesman for the U.S.-led coalition, confirmed only that peshmerga fighters raised their flag on grain silos in the eastern part of the town. He said they had not fully retaken Sinjar.

There is reason for caution. An earlier attempt to wrest back control of the town, at the foot of Sinjar Mountain about 30 miles (50 kilometers) from the Syrian border, stalled in December. Militants have since been reinforcing their ranks.