IS frees hundreds of 'human shields' in Syria

Islamic State group jihadists have released hundreds of civilians used as human shields while fleeing a crumbling stronghold in northern Syria, but the fate of others remained unknown today.

The last remaining IS fighters abandoned Manbij near the Turkish border on Friday after a rout that the Pentagon said showed the extremists were "on the ropes".

The retreat from the city, which IS captured in 2014, marked the jihadists' worst defeat yet at the hands of the Syrian Democratic Forces (SDF), an Arab-Kurdish alliance supported by US air strikes.

Fleeing jihadists took around 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.

A woman burned a black robe that the jihadists had forced residents to wear, while men who had lived for weeks under a shaving ban cut their beards with scissors.

"The battle was very hard," a Kurdish source told AFP.

"And the jihadists 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," this source said.

The Syrian Observatory for Human Rights, a British-based monitor, reported that several hundred of the civilians taken from the city were no longer being held by IS.

"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 launched an assault in May on Manbij, on a key jihadist supply route between the Turkish border and IS's de facto Syrian capital Raqa.

The jihadists, 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.