Intense fighting is taking place in north-eastern Syria after Islamic State (IS) fighters tried to break inmates out of a Kurdish-run prison.

Axar.az reports that Kurdish-led forces backed by US air strikes have been battling militants in the city of Hasaka since Thursday.

The assault on Ghwayran prison is one of the group's most ambitious since its defeat in Syria nearly three years ago.

The overcrowded site houses 3,500 suspected IS members including some of its leaders, a monitoring group says.

Hundreds of jihadists have been recaptured since the breakout but some are still on the run, the Syrian Observatory for Human Rights said.

Kurdish security forces have surrounded the prison and are fighting for control of nearby neighbourhoods. Residents have been fleeing their homes.