Regime forces used fighter jets and helicopter gunships to pound the city and province of Aleppo on Friday, a day after violence killed at least 125 people across Syria, a watchdog said.
The fighter jets bombarded the rebel-held towns of Al-Bab and Marea near Aleppo city, while fierce battles raged around the military airport at Minnigh, also in Aleppo province, said the Syrian Observatory for Human Rights.
Rebels have staged multiple attacks on military airports in recent weeks, focusing on the eastern province of Deir Ezzor, Idlib in the northwest, and Aleppo, the key battleground province of northern Syria.
As the army has increasingly employed fighter jets and helicopters in its attacks, the rebel Free Syrian Army has made military airports a strategic target, an FSA spokesman told AFP on Thursday.
Activists on Friday called for protests after the weekly Muslim prayers under the slogan, "Idlib: Cemetery of the planes and symbol of victory".
In the central Aleppo district of Midan, regime forces conducted air strikes against two police stations which the rebels had overtaken, Observatory director Rami Abdel Rahman told AFP by phone.
"Now no one controls these posts," he said, adding that "regime forces have deployed throughout Midan to try and push out the rebels."
In the Hanano district in the northeast of Aleppo city, air strikes destroyed another police station in the hands of the rebels, Abdel Rahman said.
Near the capital, at least 15 soldiers were killed or wounded in an attack on their vehicle in the restive town of Douma on Friday, as clashes broke out near the municipal building, according to the Britain-based Observatory.
Also in Douma, located northeast of Damascus, two civilians were killed as gunfire and army shelling broke out before dawn.
And in the capital on Friday, three large explosions were heard in the late morning, according to an AFP reporter.