Hundreds of Kurdish militiamen streamed into Sinjar on Friday, officials said, routing Islamic State militants who had held the town in northern Iraq for more than 15 months.
Kurdish fighters "entered Sinjar town from all four directions to clear remaining ISIL terrorists from the area," said a statement issued early Friday by the Kurdistan Region Security Council, using one of the acronyms for Islamic State, which last year seized much of northern Iraq.
It was not immediately clear, however, whether the town had fully fallen to the peshmerga, as the fighters from the semi-autonomous Kurdish region of northern Iraq are known.
The announcement came on the second day of a wide-scale U.S.-backed operation aimed at denying the extremist group access to Highway 47, a strategic supply corridor linking Islamic State's prize cities: Mosul, in northern Iraq and Raqqah in neighboring Syria.
The Kurdish advance came on the day that Syrian rebels drove Islamic State fighters out of an area about 40 miles west of Sinjar on the Syrian side of the border.
Dubbed Operation Free Sinjar, the offensive in Sinjar was launched by about 7,500 Kurdish fighters backed by heavy airstrikes from warplanes of the U.S.-led coalition.
They were joined by irregular fighters from the Yazidi sect, many of whose members were slain, routed or enslaved last year by Islamic State fighters who swept into Iraq from Syria.
"We fulfilled what we had promised, and today Sinjar is liberated," Iraqi Kurdish President Massoud Barzani said in a televised address from Sinjar, the local Rudaw News reported.
Barzani also thanked the United States and the coalition for aerial support.
"The war against Daesh is not our war alone but is the war of everyone," he said, referring to Islamic State by an Arabic acronym.
Activists posted pictures on the Internet of what they said were the corpses of dozens of Islamic State fighters, and Sumariya News quoted a source in a Mosul hospital as saying the bodies of 120 militants had been delivered there from the Sinjar area.
Kurdish and U.S. officials had estimated that least 600 militants were in the town.
Video images on social media also showed irregular fighters tearing down the extremist group's black-and-white flag or standing triumphantly over militants killed in the fighting.
Yet observers spoke of peshmerga entering the town almost unopposed, a far cry from the vicious street fighting government forces had endured in earlier confrontations with Islamic State.
Pro-Islamic State media, including the group's official channel on the instant messaging platform Telegram, did not comment on the battle.
Aside from the strategic aims, the battle for Sinjar is an important symbolic victory for the peshmerga. In August 2014, they were excoriated by many for failing to protect the Yazidis, members of a religion based on Zoroastrianism who are considered to be "devil worshipers" or "infidels" by Islamic State.
After the takeover of Sinjar, the militants massacred thousands of Yazidi men while taking women and girls as slaves. Tens of thousands escaped to nearby Mt. Sinjar.
Their fate prompted the U.S. to intervene, with airdrops of supplies for Yazidis stranded on the mountain and airstrikes against Islamic State.
In his speech, Barzani emphasized the Kurdish fighters' role in the battle.
"The peshmerga took its revenge … from Daesh," he said. "No flag other than that of the Kurdistan region will be raised in Sinjar."
The Sinjar offensive coincided with a loose coalition of U.S.-backed militias in Syria gaining control over the Islamic State-controlled region of Al Hawl, near the border with Iraq.
The coalition, called the Syrian Democratic Forces, is a newly forged grouping of secular rebels dominated by the People's Protection Units, or YPG, a Syrian Kurdish militia that was recently chosen as the main U.S. partner on the ground in Syria in the fight against the Islamic State.
The YPG and associated forces had been engaged in a weeks-long fight to retake Sinjar as well as Al Hawl. The routing of Islamic State in the Syrian area is a further blow to Islamic State's goal of controlling the border between the two countries.
The YPG had trained many of the Yazidi militiamen involved in the battle for Sinjar, but YPG officials said their fighters had no operational role in this week's offensive in the town. But they nonetheless linked the two battles.
"There was no coordination with the peshmerga," Lewand Rojava, the YPG representative of the Syrian Democratic Forces, said in a phone interview Thursday from the Syrian city of Hasakah. "But we believe the offensive had begun due to gains we had made in Al Hawl."
Bulos is a special correspondent.