On Sunday in northeastern Syria, the Observatory and Syrian state media said government troops had pushed IS fighters back from Hasakeh city after fierce fighting.
IS began an assault on city, which is capital of the province of the same name, on May 30, that has left 119 dead, among them 71 regime forces and 48 IS fighters, 11 of them suicide bombers.
By Thursday IS had advanced to the city's southern entrance.
"IS, which has been at the southern entrance of the city since Thursday, was forced to pull back two kilometres after fierce combat with regime forces," the Britain-based monitor said.
Syria's official SANA news agency also reported the fighting, saying the army had retaken several positions captured by IS in recent days, including an electricity station and a prison being used as a military base.
The Observatory said fighting was now continuing in the area near the prison.
Control of Hasakeh city is shared between government forces and Kurdish fighters, who did not initially enter into combat against IS.
But the Observatory said Kurdish forces began fighting IS on the outskirts of the areas under their control in the west of the city on Saturday night.
Syria's Kurds have walked a careful line in the country's conflict, declining to join the uprising directly, but also not fighting alongside the regime.
In Hasakeh, they share control of the city's security with regime forces, but the arrangement has been tense at times with skirmishes breaking out occasionally.
Also on Sunday, the Observatory reported that 17 people were killed in three barrel bomb attacks launched by regime forces in the north of the central province of Homs.
AFP
