Rebels are believed to have shot down a a Syrian army helicopter over a Damascus neighbourhood, with video footage showing the burning craft falling from the sky.
Syrian state television reported that a helicopter had been downed but offered no further details about who might be responsible.
Al-Arabiya ran video footage apparently taken by rebel activists, showing the helicopter in a ball of flames, and shouting was heard in the background: "God is great."
The destruction of houses by shelling from Syrian government forces in Damascus, Syria
Heavy fighting between the Free Syria Army and government forces began early on Monday morning.
The Syrian Observatory for Human Rights said explosions and gunfire had been heard across the capital.
New shelling on Monday killed three men, three children and two women in Kafr Batna, close to Damascus, the Observatory added.
President Bashar al-Assad and his forces are accused of a massacre in the town of Daraya near Damascus, believed to have left hundreds dead, according to the Observatory.
Footage from the killing, of at least 320 people, shows hundred of bodies covered in blood, lined up in a graveyard and in a mosque.