Over 120 killed in IS prison attack: monitor

At least 120 people have been killed in Syria including seven civilians as battles between US-backed Kurdish forces and Islamic State group fighters raged for a fourth day, a war monitor said Sunday.

Fighting began late Thursday with an assault by more than 100 IS insurgents on the Kurdish-run Ghwayran jail in Hasakeh city -- which housed the largest number of jihadists in the country -- marking the group's most significant operation since its "caliphate" was declared defeated in Syria nearly three years ago.

Ongoing battles have seen IS fighters free fellow jihadists and seize weapons stored at the jail, according to the Britain-based Syrian Observatory for Human Rights, in what experts have described as a blatant regrouping attempt.

"At least 77 IS members and 39 Kurdish fighters, including internal security forces, prison guards and counter-terrorism forces have been killed" in violence inside and outside the prison since the start of the attack, the Observatory said.

At least seven civilians have also been killed in the fighting, according to the monitor.

Weapons and captives

Battles continued for a fourth consecutive day on Sunday as the Kurdish-led Syrian Democratic Forces, backed by coalition strikes, closed in on jihadist targets inside and outside the facility. 

"Fierce clashes broke out overnight Sunday... as part of an ongoing attempt by Kurdish forces to restore control over the prison and neutralise IS fighters deployed in surrounding areas," said the Observatory, which relies on a network of sources inside Syria.

The war monitor said that Kurdish forces have managed to recapture more than 100 IS detainees who had tried to escape but many more remain on the run. Their exact numbers remain unclear. 

In a statement released on its Amaq news agency overnight, IS claimed that it took over a weapons storage room in the prison and freed hundreds of fellow jihadists since the operation began with a double suicide bombing.

A video it released on Amaq purported to show IS fighters carrying the group's black flag as they launched the attack on the facility and surrounded what appears to be a group of prison guards.

A second video also released on Saturday showed several men that IS said it had abducted as part of the attack on the jail, including some dressed in military fatigues.

AFP could not independently verify the authenticity of the footage. 

Commenting on the video, the Kurdish-led Syrian Democratic Forces said the captives were "kitchen staff" from the jail.

"Our forces lost contact with them during the first attack," the SDF said in a statement, without elaborating.