(CNN) Kurdish forces liberated the northern Iraqi town of Sinjar from ISIS on Friday after just a two-day offensive, a Kurdish leader said, reversing the terror group's takeover of a community where thousands were massacred and tens of thousands were forced to flee 15 months ago.

The Peshmerga -- the Iraqi Kurdish military force -- unfurled an enormous Kurdish flag over silos in Sinjar in a symbol of conquest, just the latest territory that Kurds have captured from ISIS in areas near the region they inhabit in Iraq, backed by air power from a U.S.-led coalition.

"Sinjar has been liberated by the Peshmerga," said Masoud Barzani, leader of Iraq's Kurdish autonomous region, as he stood in front of reporters on a plateau overlooking Sinjar on Friday afternoon.

Sinjar silo, cement factory, hospital and several public buildings now secured by brave Peshmerga. ISIL defeated and on the run. #FreeSinjar

Pockets of resistance remained, according to CNN senior international correspondent Nick Paton Walsh, who walked in the town with the Peshmerga in the afternoon. A bullet, apparently fired toward the Peshmerga, whizzed past the group at one point, prompting the Kurds to return fire.

The importance of Sinjar in the fight against ISIS

The importance of Sinjar in the fight against ISIS 00:55

The importance of Sinjar in the fight against ISIS

"There are still people resisting," Paton Walsh said, though the Kurds had effectively retaken Sinjar "without a doubt."

Up to 7,500 Peshmerga troops, backed by coalition air power, appeared to quickly overwhelm ISIS fighters when the offensive began Thursday. Peshmerga commanders estimated that some 600 ISIS fighters were inside the town.

The town's immediate value to its former residents is questionable, with nearly every building damaged, some apparently by coalition airstrikes.

Photos: Agony of the Yazidis Photos: Agony of the Yazidis A Yazidi woman kisses the hand of a relative before a bus takes women and children who were captives of ISIS to an airport in the Kurdish region of Iraq. From there, they will fly to Germany, where the German government is resettling up to 1,000 former captives of ISIS, giving them housing and psychological treatment. Hide Caption 1 of 8 Photos: Agony of the Yazidis Sabah Mirza Mahmoud, right, cries next to his uncle Jamil Jato as Mahmoud and his sisters prepare to leave for Germany. Hide Caption 2 of 8 Photos: Agony of the Yazidis Baba Sheikh, the Yazidi spiritual leader, speaks to Yazidi women and girls who were captives of ISIS before their journey to Germany. Hide Caption 3 of 8 Photos: Agony of the Yazidis A Yazidi girl faints while saying goodbye to relatives who are going to Germany. Hide Caption 4 of 8 Photos: Agony of the Yazidis Jamil Jato shows photos of family members who were murdered by ISIS. Hide Caption 5 of 8 Photos: Agony of the Yazidis Two older Yazidi men talk under a tree. Hide Caption 6 of 8 Photos: Agony of the Yazidis Women and children wave goodbye to relatives before their journey to Germany. Hide Caption 7 of 8 Photos: Agony of the Yazidis A Yazidi man lights a ritual oil candle at sunset. Hide Caption 8 of 8

But the capture of Sinjar -- which is on a highway connecting ISIS' territory in Syria to its largest conquered city, Mosul in Iraq -- is a step toward dividing the "caliphate" that ISIS claims it has been establishing across portions of the two countries.

The Peshmerga, which protect Iraq's Kurdish region in the country's north and northeast, have been among the more effective forces opposing ISIS in Iraq. Barzani told reporters Friday that Sinjar is a step toward a future liberation of Mosul, which ISIS took in 2014.

"Without doubt, the liberation of Sinjar will have a large effect on the liberation of Mosul," Barzani said of Iraq's second-largest city.

Tens of thousands fled last year

The apparent liberation of Sinjar comes more than a year after ISIS brutally captured the town, forcing tens of thousands to flee as the world watched in horror.

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The town was a home to Yazidis, among Iraqi's smallest minorities. As ISIS conquered Sinjar in August 2014, about 5,000 men and boys in the town and nearby villages were massacred, according to U.N. estimates, while teenage girls and women were sold into slavery

Some 50,000 Yazidis in the region scrambled up Mount Sinjar to escape the ISIS onslaught.

After that, Sinjar became a chaotic jumble of demolished buildings held by ISIS fighters.

"There is no reliable estimate as to how many civilians are still live inside of Sinjar," Paton Walsh said.

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Many displaced Yazidis still are migrating from their homeland. As this week's battle for Sinjar raged, a rubber dinghy crammed with refugees -- many of them Yazidi men, women and children -- arrived on the Greek island of Lesbos, having crossed part of the Aegean Sea from Turkey, its occupants hoping to make new lives in Europe.

A Yazidi man named Jamal made the trip with his family, having fled Sinjar when ISIS arrived last year. They had lived in a tent in the neighboring Iraqi Kurdish region for a year before heading to Greece.

Clutching one of his children, he told CNN's Arwa Damon that even if Sinjar was retaken, there was likely nothing to immediately return to.

"If this child grows up there, where will he go? No school, no work. Is this a life?" Jamal said.

Sinjar's strategic importance

One reason Sinjar is important in the overall battle against ISIS: The artery that passes through town -- Route No. 47 -- links ISIS-held Mosul with ISIS' holdings in Syria.

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Paton Walsh said the highway was a key goal for the Kurdish fighters, who were equipped with vehicles ranging from pickup trucks to armored Humvees.

On Friday, they had retaken key sections of the highway, cutting off the ISIS supply route around Sinjar.

U.S.-backed coalition airstrikes helped pave the way for the Peshmerga.

Operation Inherent Resolve said coalition aircraft have conducted more than 250 airstrikes across northern Iraq in the last month. The strikes have reportedly destroyed ISIS fighting positions, command and control facilities, weapon storage facilities, improvised explosive device factories and staging areas.

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According to a Pentagon spokesman, U.S. troops were in the field, calling in airstrikes from positions in the Sinjar area.

Speaking to CNN's Fareed Zakaria earlier this week, U.S. Secretary of State John Kerry explained the U.S. strategy.

"President Obama, at the very beginning, said we're going to degrade and defeat ISIL," Kerry said, using an alternate acronym for ISIS. "We're going to stabilize the countries in the region -- Jordan, Lebanon, work with Turkey -- and we are going to seek a political settlement," he said. "That is exactly the strategy today and it is working -- to a degree -- not as fast as we would like, perhaps, but we are making gains."

Neighbors united

With the operation to retake the town looming, some 5,000 Yazidi fighters were mobilized under the command of the Kurdish Peshmerga. Most were farmers; a very few had military experience.

The Yazidis are one of the world's smallest and oldest monotheistic religious minorities. Their religion is considered a pre-Islamic sect that draws from Christianity, Judaism and the ancient monotheistic religion of Zoroastrianism. In ISIS' eyes, they're infidels.

The Yazidis and Kurds have lived side by side for thousands of years and are friendly neighbors.