Syrian forces 'kill many rebels' in Eastern Ghouta
Syrian government forces have ambushed and killed a large number of Islamist rebel fighters in the eastern outskirts of the capital Damascus, reports say.
Syrian state media say 175 died.
The UK-based Syrian Observatory for Human Rights says it has received reports that about 70 died in the fighting in the Eastern Ghouta region.
The Observatory, which is close to the rebels, also said about 3,300 people had been killed in fighting between rebel factions so far this year.
"Some 3,300 people have been killed ever since the start of fighting on January 3 between the Islamic State of Iraq and the Levant on one side, and Islamist and other groups on the other," it said. The deaths came in "car and (other) bomb attacks, suicide blasts and fighting", it added.
The Eastern Ghouta is part of an agricultural belt around Damascus where a chemical weapons attack killed hundreds of civilians last year.
Western intelligence agencies and human rights activists blamed the attack on Syrian forces, but the Syrian government and its allies said rebels had carried it out.
Some analysts suggest Wednesday morning's army operation - said to have taken place near Otaybeh village - may have tightened President Bashar al-Assad's grip on Damascus.
Images and footage from the scene showed the bodies of dozens of men - some dressed in military fatigues, others in civilian clothes - lying on a dirt track in a rural area, and also government tanks and armoured personnel carriers.
Lebanese Hezbollah's al-Manar TV station reported that the fighters were trying to break out of Eastern Ghouta to join battles in either the town of Deraa or the Qalamoun mountains.
"Acting on information and in a well-organised ambush, our courageous army killed dozens of terrorists, most of them non-Syrians," said Syrian state television.
The Observatory said: "Dozens of Islamist fighters were killed and wounded in an ambush by loyalist troops, with the help of (Lebanese Shia group) Hezbollah."
State news agency Sana said the fighters were mainly Saudis, Qataris and Chechens who were members of two Islamist groups - Nusra Front and Jaish al-Islam - and that the army operation had dealt "a smashing blow to terrorists''.
But Jaish al-Islam said the dead were civilians, trying to escape a siege. In a statement on social media, it said it had not lost any fighters.
Syria's war has killed more than 140,000 people and forced millions to flee since March 2011.
Also on Wednesday, a United Nations official called on all sides in the conflict to allow aid workers to resume distribution of food and medicine in a besieged Palestinian district of Damascus.
Chris Gunness of the UN relief agency Unrwa urged them to grant "safe and unhindered humanitarian access'' to thousands of trapped civilians in the Yarmouk camp, which has seen severe food shortages and widespread hunger amid fierce fighting.
Meanwhile, diplomats quoted by the Reuters news agency said the Syrian government had agreed a new timetable to give up all its chemical weapons under international supervision by late April after failing to meet a deadline earlier this month.
The Organisation for the Prohibition of Chemical Weapons, which is overseeing the process along with the United Nations, said a fourth consignment of Syrian chemical weapons, containing mustard gas, had left the country on Wednesday.
It welcomed the move, but called on Damascus to "maintain momentum" in shipping out the chemicals.
Correction 4 March 2014: This report has been amended to give a wider range of views on the chemical weapons attack.