Syria's Kurdish-led forces find ISIS militants hiding in Ghwayran prison

Assault on sprawling facility near Hasakeh sparked fighting that claimed 235 lives

Kurdish-led forces on Thursday found dozens of militants holed up in a Syrian prison during mop-up operations after recapturing the facility from ISIS fighters.

An ISIS assault on the sprawling Ghwayran prison near the city of Hasakeh on January 20 sparked six days of fighting that claimed at least 235 lives.

It was the most high-profile attack launched by ISIS since the loss of their self-proclaimed caliphate nearly three years ago.

The Kurdish-led Syrian Democratic Forces (SDF) said they had retaken full control of Ghwayran prison on Wednesday, ending battles that turned northeastern Syria's largest city into a war zone.

But search operations the next day found around 60 to 90 militants still holed up in one wing of the prison, the SDF said in an AFP report. A total of 3,500 ISIS members had surrendered.

"Our forces have made a call for safe surrender... and in case they did not surrender, we will deal with them firmly," said a statement from the SDF, the semi-autonomous Kurdish administration's de-facto army.

Sporadic clashes broke out again on Thursday in the vicinity of the prison compound during the Kurdish mop-up operations, killing at least 12 militants, the Britain-based Syrian Observatory for Human Rights said.

The bodies of five others were found inside the prison, the war monitor said.

Hasakeh entered its fourth day in lockdown with US-backed Kurdish forces blocking all entrances to the city to keep fleeing jihadists from crossing into other areas.

Around 45,000 people fled their homes in Hasakeh to escape the violence, according to the UN, with many taking shelter in mosques or wedding halls in the city.