BEIRUT: Syrian rebels downed a warplane over the Damascus provincial town of Hammuriyeh on Wednesday, shortly after an air strike killed at least nine people and wounded dozens more there, a watchdog and activists said.

Amateur video shot by activists and distributed by the Syrian Observatory for Human Rights showed a warplane firing from the sky and then going down in flames after apparently being hit.

"It's gone up in flames! Allahu akbar (God is greatest)! The (rebel) Free Syrian Army air defence battalions have hit a MiG warplane!" cried the amateur cameraman shooting the video.

Lacking sophisticated weaponry, rebels fighting the regime of President Bashar al-Assad have frequently used heavy machineguns to shoot down warplanes deployed to strike insurgent enclaves across the country.

"The shelling and bombardment in Eastern Ghuta province on Wednesday was fierce," Observatory director Rami Abdel Rahman told AFP.

Elsewhere, troops fought rebels around several air bases and the international airport in the northern city of Aleppo, the Observatory said.

"The clashes around Kwayris military airport were fierce today, and there were also intermittent battles around Aleppo international airport and Nayrab military air base," Abdel Rahman said.

Rebels launched an assault last week to seize several air bases and the Aleppo airport, in a bid to stop warplanes from taking off and to seize ammunition.

In the past week, rebels have captured air bases at Al-Jarrah, Hassel and Base 80, as well as an important checkpoint near the international airport.

Wednesday's violence came a day after some 100 people were killed across Syria, according to the Observatory.

The UN says more than 70,000 people have been killed in Syria's nearly two-year war, most of them civilians.