Syrian President Bashar Assad sent helicopters to bomb rebel positions in Damascus and warplanes and thousands of troops to strafe Aleppo in his brutal war to stay in power.   

Recent days have seen Syria's 16-month-old uprising transformed from an insurgency in remote provinces into a battle for control of the two main cities, Aleppo and the slightly smaller capital, Damascus, where fighting exploded last week.

Assad's forces appear to have beaten rebels back from neighborhoods in the capital and are turning towards Aleppo, a commercial hub in the north.

Syrian forces fired artillery and rocket barrages early on Wednesday at the northern Damascus suburb of al-Tel in an attempt to seize the area from rebels, causing mass panic and forcing hundreds of families to flee the area, residents and opposition activists said.

"Military helicopters are flying now over the town. People were awakened by the sound of explosions and are running away," Rafe Alam, one of the activists, said by phone from a hill overlooking Tel, a suburb of approximately 100,000 people. "Electricity and telephones have been cut off."

Opposition activists said thousands of troops had withdrawn with their tanks and armored vehicles from a strategic area near the Turkish border and were headed towards Aleppo. Rebels attacked the rear of the troops withdrawing from the region and were battling government forces by the gates of the historic old city, while government helicopters fired missiles from overhead.

"I heard at least 20 rockets fired, I think from helicopters, and also a lot of machinegun fire," a resident near one of the areas being shelled, who asked to be identified only by his first name Omar, said by telephone.

"Almost everyone has fled in panic, even my family. I have stayed to try to stop the looters; we hear they often come after an area is shelled."

Residents said fixed-wing jets had also flown over the city, followed by loud noises, although there were contradictory reports as to whether they had fired.

The civil war took a dramatic change last week when a bomb explosion wiped out much of the top echelon of Assad's military command structure and shattered the reputation for invulnerability that his family has held since his father seized power in a 1970 coup.

Assad has been able to continue his brutal suppression of the 16-month-old rebellion by virtue of the international community’s fear of intervening, despite the worsening humanitarian disaster. More than 16,000 civilians and opposition fighters have been killed, and hundreds of thousands others have been wounded or left homeless.

Western jawboning has had virtually no effect on Assad, but behind-the-scenes arming of Syrian rebels has enabled them to strike back at the Syrian army, despite its overpowering arsenal.

Elsewhere in the country, activists said government troops and pro-Assad militia known as shabbiha had attacked a mosque in a village northwest of the city of Hama.

"We have confirmed the names for 15 bodies and it is estimated there is a similar number still to be collected from the streets," said Jamil al-Hamwi, who uses a pseudonym for security reasons. The account, like others from activists, could not be confirmed. Syria restricts access by international journalists.