An amateur video showed an opposition activist clutching what appears to be the bodies of two newborns and accusing Syrian President Bashar al-Assad of responsibility for their deaths.
Activists claim Syrian troops on Wednesday unleashed an artillery and rocket barrage that included some toxic agents against several Damascus suburbs.
The activists posted videos online showing scores of bodies of adults and children laid out on the floor of makeshift clinics with no visible signs of injuries.
Alleged casualty figures were contradictory with some opposition activists claiming that as many as 1,600 people were killed and others putting the death toll at several hundred.
The alleged attacks came several days after United Nations weapons inspectors arrived in Damascus to investigate previous alleged attacks of chemical weapon use by the government and rebels.
Top Syrian opposition leader George Sabra told a press conference in Istanbul that the Syrian government has shown disrespect for the inspectors and their mission.
"The Syrian government has mocked the inspectors by placing restrictive conditions on their ability to investigate. Evidence has either deteriorated or been destroyed and the Syrian government anticipates that any condemnation will be hollow," said Sabra.
Activists wear gas masks as they look for dead bodies and collect samples to check for chemical weapon use in Zamalka, Damascus, August 22, 2013.
An activist wearing a gas mask stands next to a dead dog as he looks for bodies to collect samples to check for chemical weapon use, in Zamalka, Damascus, August 22, 2013.
Syrian activists inspect the bodies of people they say were killed by toxic gas near Damascus, August 21, 2013.
A man sits in a hospital near two children who activists say were affected by toxic gas near Damascus, August 21, 2013.
People, affected by what activists say is toxic gas, are treated at a hospital in the Duma neighborhood of Damascus August 21, 2013.
A youth, affected by what activists say is toxic gas, is treated at a hospital near Damascus, August 21, 2013.
A Syrian military soldier holds his Ak-47 with a sticker of Syrian President Bashar Assad and Arabic that reads, "Syria is fine," as he stands guard at a check point on Baghdad street, in Damascus, August 21, 2013.
A Syrian military soldier checks the trunk of a car at a check point on Baghdad street, in Damascus, August 21, 2013.
A Syrian Army spokesman says government forces have not used chemical weapons against its own people but says that the government has a duty to pursue what he called “terrorists.”
"The accusations of chemical weapons use are part of an ugly media war waged by outside nations and media against Syria. The army has a duty to fight terrorism and protect its citizens. Rebel forces are making allegations in a desperate attempt to hide their defeat," he said.
Opposition activists made contradictory claims of what weapons may have been used in Wednesday's alleged attack with several claiming that long-range rockets were used and others alleging the use of smaller, multi-tube Grad rockets.
Syrian Information Minister Omran Zohbi, who has said on several occasions that Syria does not have chemical weapons, told journalists that the government would never use chemical weapons against its people:
"The military operations are taking place in the eastern suburbs of the capital and that the army is fighting terrorist groups. It would be illogical to use chemical weapons under such circumstances," said Zohbi.