At least 52 fighters and two civilians were killed yesterday in clashes between rival anti-regime groups east of Syria's capital, the Syrian Observatory for Human Rights said, reports AFP from Beirut.
The powerful Jaish al-Islam, or Army of Islam, has been locked in clashes with rival factions led by Al-Qaeda's Syrian affiliate in the opposition stronghold of Eastern Ghouta.
Observatory head Rami Abdel Rahman said nearly three weeks of fighting had killed more than 500 fighters and a dozen civilians.
One of the slain civilians has been identified as the only specialist gynaecologist still practising in Eastern Ghouta.
"This is absolutely a power struggle," Abdel Rahman told AFP. Eastern Ghouta is the largest rebel bastion in
Damascus province, and Jaish al-Islam had long been dominant in the district.
The Saudi-backed faction is one of the key rebel players in the High Negotiations Committee, which represents Syria's opposition in UN-backed peace talks.
Meanwhile, attacks including suicide bombings killed at least 48 people in Baghdad yesterday, the second time in a week the Iraqi capital has been hit by a deadly spate of bombings.
The attacks bring the toll for violence in and near Baghdad to more than 150 people killed in just seven days.
The unrest highlights the continued existence of significant flaws in Baghdad security procedures that have gone largely unaddressed even as US-led forces train Iraqi forces for the fight against the Islamic State (IS) jihadist group.
The deadliest attack hit the Sadr City area in northern Baghdad, where a suicide bomber detonated an explosives-rigged vehicle, killing at least 24 people, security and medical officials said.
IS issued a statement claiming the attack and confirming that it was carried out by a suicide bomber who detonated a car bomb.
Another attack hit the Shaab area, also in northern Baghdad, killing at least 21 people.