DAMASCUS: Syrian government troops and allied fighters captured some of the last parts of Deir Ezzor city from Daesh on Thursday, state media and a monitor said.

Syria's army has been battling inside the city since September, when it broke a militant siege of nearly three years on government-held parts of the provincial capital.

Syrian state media said Thursday that the army and allied fighters had captured three neighbourhoods in the city, and "tightened the siege" on Daesh fighters in several remaining districts.

State news agency SANA said Daesh fighters were using loudspeakers to urge remaining members of the group "not to run away from the fighting, and to kill any member who tried to escape or surrender".

The Britain-based Syrian Observatory for Human Rights monitor also reported the regime advances in the city, provincial capital of surrounding Deir Ezzor, on Syria's eastern border with Iraq.

The monitor said Daesh fighters held less than five percent of the city, and government forces were advancing as ally Russia carried out heavy air strikes in support of the offensive.

"If the regime's forces succeed in continuing this offensive, they could bring an end to IS´s presence (in the city) in hours or days," the Observatory said.

Daesh once held large sections of Deir Ezzor city, and for nearly three years laid siege to other parts of it that remained under government control.

In early September, advancing government forces broke the siege, and they have been working since to expel the jihadists from the rest of the city.

Oil-rich Deir Ezzor province was once an Daesh stronghold, but the militant group now faces twin assaults there, from the regime and the US-backed Kurdish-Arab Syrian Democratic Forces.

The militants have already been expelled from neighbouring Raqqa province, and are now confined to just a few pockets of territory in Deir Ezzor.