BEIRUT  - Rebels launched assaults to try to take strategic airports in northern Syria on Thursday, after the United Nations revealed that the country’s civil war had already killed 60,000 people.

Insurgents battled with troops on the perimeter of the Aleppo international airport, besieging the nearby military Brigade 80 in an attempt to push through to the airport itself, the Syrian Observatory for Human Rights said.

At the same time, hundreds of fighters with two hardcore rebel groups, the Al-Nusra Front and Ahrar al-Sham, fought soldiers around the Taftanaz airbase in the northwestern province of Idlib, the watchdog said.

The rebels had broken into the airbase the day before after launching a car bomb at the main gate but were pushed back by the army.

The Aleppo airport is a strategic prize in Syria’s north, which is largely under rebel control.

It has been closed since Tuesday after repeated attacks by rebels, according to an airport official, who said the civilian facility would reopen as soon as the army regained control of the surrounding areas.

Fighting in Aleppo city has been at a stalemate for months since opposition fighters launched a massive assault in mid-July.

Troops retaliated against rebel gains by bombarding a string of towns northwest of Aleppo, including Hayan, where air strikes killed five civilians, including women and children.

Warplanes also struck town of Aazaz near the Turkish border, the British-based Observatory said.

Fighting also raged around the Deir Ezzor military airport, where three rebels were killed, and in the nearby provincial capital in the east of the country.

The rebels control large swathes of land stretching from Deir Ezzor city to the border with Iraq further east.

Meanwhile warplanes also pounded rebel strongholds northeast of Damascus, killing at least seven people in Douma, the Observatory said.

In the capital itself fierce clashes erupted in the eastern Zablatani while loud explosions and gunfire shook Tadamun in the south.

The army also bombed a string of rebel positions along the Damascus airport road and the town of Maliha, where dozens were killed or wounded in an air raid on a petrol station Wednesday, the watchdog said.

Thursday’s violence killed at least 39 people nationwide, most of them civilians, it added.

The United Nations on Wednesday said 60,000 people have been killed in the 21 months since Syria’s rebellion started from a revolt in March 2011.

The figure, described as “truly shocking” by UN High Commissioner for Human Rights Navi Pillay, was nearly a third higher than the toll previously given by the Observatory.