At least 60,000 people have been forced to flee the north-eastern Syrian city of Hassakeh as Islamic State fighters launched an attack, killing dozens, ABC News reported.

Syrian government forces and allied paramilitary National Defence Forces earlier regained control of the neighbourhood of eastern Ghoweiran, which fell in the hands of Islamist extremists last week.

The jihadist group captured three predominantly Arab neighbourhoods in Hassakeh last week. Fighting is still continuing in the city, according to Mustafa Osso, an opposition figure based in Turkey.

People trapped in the besieged Syrian city urgently need food, water, shelter and medical assistance, according to Sam Duerden, an Iraq-based International Rescue Committee official.

At least 10,000 have been staying in schools or community centres, while many have fled to nearby villages and towns, sources said.

"It's a big movement. People have talked about the city basically emptying out," Duerden said.

Those escaping the city are mostly women and children, including those already forced out of their homes from other war zones.

"We've also been seeing families split up, separated families, unaccompanied children, since many people had to leave quickly on foot."

ISIS fighters killed 12 soldiers and pro-government men when they detonated three car bombs in the city, said the Britain-based Syrian Observatory for Human Rights.

The US-led coalition has already launched seven overnight airstrikes near the city, hitting five groups of jihadist fighters, sources said.

The airstrikes also destroyed an armoured personnel carrier, a tank, and four vehicles, the sources added.

Hassakeh, which has a mainly Kurdish population, was split between Kurdish fighters and government forces until the ISIS' latest advance.

Syria's five-year civil war has already left over 220,000 people dead and displaced almost half of the country's pre-war population of 23 million.