The Syrian government issued a denial and said the allegations were aimed at derailing a mission currently underway by United Nations chemical weapons inspectors.
“What is being aired by channels like Al Arabiya and Al Jazeera only supports terrorism and is an attempt to obstruct the mission of the UN chemical weapons experts in Syria,” the government said, according to state news agency SANA.
The areas targeted in eastern Damascus were Eastern Ghouta and Mazamiyet al-Sham, said the Syrian Observatory for Human Rights, a pro-opposition watchdog group based in Britain.
Syrian Local Coordination Committees, a pro-opposition group that documents violence across the country, said 635 people had been killed in the attacks.
The attacks and casualties could not be independently verified.
But activists posted photographs online purportedly showing a makeshift hospital with people, including children, screaming, struggling to breathe, and being treated as they lay on the floor.
“We are trying to compile a list of the number of the victims at least in 10 areas, which were targeted by the regime forces,” said Louay Mokdad of the rebel Free Syrian Army.
A 20-member UN team, led by Swedish chemical weapons expert Ake Sellstrom, arrived in Damascus on Sunday to investigate three sites of alleged chemical weapons attacks.
“If the UN team came to Syria just to stay in an hotel in Damascus, then let them go back home. These massacres were committed few kilometres away from the hotel where they are staying in,” Mokdad told DPA.
Arab League chief Nabil al-Arabi condemned what he called a “horrendous crime killing hundreds of innocent Syrian civilians.” “The (UN) inspectors have to go immediately to the Eastern Ghouta to verify the situation and investigate the circumstances of this crime, which represents a serious violation of international law,” he said.
Al-Assad’s government asked the UN to investigate an alleged chemical weapons attack on March 19 in the northern area of Khan al-Assal that was captured by the rebels last month.
The government and rebels have blamed each other for the purported attack, in which at least 30 people were killed.
British Foreign Secretary William Hague called on the Syrian government to allow the UN team immediate access to the area of Wednesday’s alleged attack.