Over the past few weeks more than 3,000 Iranian snipers have arrived in Damascus to aid the forces loyal to Syrian President Bashar Assad,
Al-Arabiya reported, citing a leader of one of the rebel groups operating in the civil war-torn country.
The head of the Joint Military Council, one of the groups fighting to maintain control of the city of Aleppo,
told the Dubai-based television network that the Syrian army no longer trusts its local troops, who are now considered potential defectors.
Meanwhile, a former Syrian soldier who defected from Assad's ranks to join the rebels claimed that the embattled Syrian president is staying in an underground hideout located in a mountainous area behind his Damascus
According to Khaled al-Hamoud, the building belongs to the president's brother, Maher Assad, and his wife.
Syrian tank abandoned in Aleppo (Archive photo: AFP)
"The Syrian leader's entire family is there," he told Asharq Alawsat. "We have the exact coordinates of the site, as well as other strategic sites, including chemical weapon caches."
Clashes in Aleppo continued on Saturday, activists and witnesses reported. A Syrian army helicopter fired machinegun rounds on the city, a Reuters witness said, as Syrian troops fired artillery shells to break through the rebels' frontline in the battleground district of Salaheddine.
"There is one helicopter and we're hearing two explosions every minute," a Reuters reporter said.
In Salaheddine, rebels from the Free Syria Army hid in alleyways, dodging the Syrian army's bullets and tank rounds that struck a building in the district.
Earlier, Al-Arabiya cited the Free Syrian Army (FSA), another rebel group, as claiming it was in control of around 60% of Syria's largest city.
The FSA also said it was able to seize control of buildings housing radio and television stations, but later had to retreat after the regime's army helicopters shelled them.
Captain Hussam Abu Mohammed, who participated in the battles around the buildings, said that the army’s retreat was “tactical.”
The Syrian Observatory for Human Rights confirmed rebel forces withdrew from the district of Izaa, where the state television building is situated.
“Rebel forces planted explosives there, and regime forces shelled the area,” the Britain-based Observatory reported. “The rebels then withdrew from the area.”
Witnesses also said heavy explosions have been heard since dawn in Damascus. Helicopters were seen circling the sky.
Syrian rebels appeared to be renewing an offensive in the capital only two weeks after the government crushed a rebel run on the city. The fresh battles Saturday show that Assad's victories could be fleeting as armed opposition groups regroup and resurge.
Syria's uprising began in March 2011 with mostly peaceful protests against the regime, but the conflict has transformed into a civil war. Activists estimate 19,000 people have been killed.
AP and Reuters contributed to the report