US officials say coalition's intention is to next move on Raqqa, de facto capital of IS 'caliphate'
Islamic State (IS) group militants have released hundreds of civilians they used as human shields while fleeing a crumbling stronghold in northern Syria, but the fate of others remained unknown on Saturday.
The last remaining IS fighters abandoned Manbij near the Turkish border on Friday after a rout that the Pentagon said showed the militants were "on the ropes".
The retreat from the city, which IS captured in 2014, marked the militants' worst defeat yet at the hands of the Syrian Democratic Forces (SDF), an Arab-Kurdish alliance supported by US air power.
Fleeing fighters took about 2,000 civilians, including women and children, on Friday to ward off air strikes as they headed to the IS-held frontier town of Jarabulus, according to the SDF.
At least some of the civilians were later released or escaped, the alliance said on Saturday, but the whereabouts of the rest was unknown.
"There are no more IS fighters" left in Manbij, an SDF member said.
Kurdish television showed footage of jubilant civilians in Manbij, including smiling mothers who had shed their veils and women embracing Kurdish fighters.
One woman burned a black robe that the militants had forced residents to wear, while men who had lived for weeks under a shaving ban cut their beards.
"The battle was very hard," a Kurdish source told AFP, adding that the militants had laid mines in the city.
"One SDF fighter entered a house on Friday and saw a shoe placed on a Koran. When he removed it there was an explosion and he was killed," the source said.
Britain-based monitor the Syrian Observatory for Human Rights reported that several hundred of the civilians taken from Manbij were no longer being held.
"Among the civilians taken by IS there were people used as human shields, but also many who chose voluntarily to leave the town due to fear of reprisals" by the SDF, Observatory head Rami Abdel Rahman said.
The SDF began an assault in May on Manbij, on a key militant supply route between the Turkish border and IS's de facto Syrian capital Raqqa.
The militants, who have suffered a string of losses in Syria and Iraq, have often staged mass abductions when they come under pressure to relinquish territory they hold.
IS has also booby-trapped cars and carried out suicide bombings to slow advances by their opponents.
SDF forces captured Manbij on 6 August, but continued to battle pockets of resistance.
According to the Observatory, 437 civilians, including more than 100 children, were killed in the battle for Manbij and surrounding territory.
About 300 SDF fighters died, along with more than 1,000 militants, it said.
Pentagon deputy press secretary Gordon Trowbridge said on Friday that IS "is clearly on the ropes".
"It has lost the centre of Manbij, it has lost control of Manbij," he said.
Since the battle for Manbij began, US-led strikes have destroyed more than 50 IS heavy weapons and more than 600 fortified fighting positions, Trowbridge said.
US officials have said that after Manbij, the coalition's intention is to move on Raqqa, the BBC reported.
Raqqa, estimated to have a population of between 250,000 and 500,000, has become the de facto capital of the "caliphate" whose creation was proclaimed by IS two years ago after it took control of large swathes of territory in Syria and Iraq, the BBC said.
Syria's conflict erupted in March 2011 and has since killed more than 290,000 people and drawn in world powers on all sides of the war.