Beirut - Syria‘s main Opposition group accused the government of “massacring” more than 1,300 people in a chemical weapons attack on Wednesday on rebel areas near Damascus, stating many of the victims choked to death.

The claim of a chemical attack, which could not be independently verified, was vehemently denied by the Syrian regime which said it was intended to hinder the mission of UN chemical weapons inspectors now in the country.

Videos distributed by activists, the authenticity of which could not immediately be verified, showed medics attending to suffocating children and hospitals being overwhelmed.

More footage showed dozens of people laid out on the ground, among them many children, some of them covered in white sheets.

The Local Coordination Committees (LCC), a network of activists, reported hundreds of casualties in the “brutal use of toxic gas by the criminal regime”.

And in videos posted on YouTube, the Syrian Revolution General Commission, another activist group, showed what it called “a terrible massacre committed by regime forces with toxic gas.”

The attack “led to suffocation of the children and overcrowding field hospitals with hundreds of casualties amid extreme shortage of medical supplies to rescue the victims, particularly Atropine,” the LCC said.

Eastern Ghouta“was also shelled by warplanes following the chemical attack that is still ongoing, which led to hundreds of casualties and victims, among them entire families,” it said.

In one video, children are seen being given first aid in a field hospital, notably oxygen to help them breathe. Doctors appear to be trying to resuscitate unconscious children.

“Genocide! Genocide in the town ofMoadamiyetal-Sham (southwest ofDamascus) using chemical weapons,” cries the man behind the camera.

His voice trembling with fear, he adds: “Where are my parents? Where is my father? My mother?”

“People working in the field hospital are overwhelmed and unable to do anything for the wounded. There is a severe lack of medicines. The wounded are being treated using just water and onions,” Abu Jihad, an activist in Irbin, told AFP via the Internet.

“This regime considers children in liberated areas to be its enemies,” Eastern Ghouta-based Abu Nadim said via the Internet.

The opposition National Coalition’s George Sabra, who spoke to reporters in Istanbul, gave a toll of more than 1,300 people dead in what he said was a “coup de grace that kills all hopes for a political solution in Syria”.

“The Syrian regime is mocking the UN and the great powers when it strikes targets nearDamascus, while the (UN weapons inspectors) are just a few steps away,” he added.

State news agencySanasaid “reports on the use of chemical weapons in Ghouta are totally false. It’s an attempt to prevent the UN commission of inquiry from carrying out its mission.”

The agency described Wednesday’s violence as “a series of operations” by army units “against terrorist groups” in Jobar, Irbin and Zamalka, “killing a number of them and destroying their hideouts”.

In a statement, the army flatly denied as “null, void and totally unfounded” the opposition’s allegations, describing them as a “desperate bid to conceal their failures on the battlefield”.

UN engages Damascus: Chief UN chemical weapons inspector Ake Sellstrom is holding discussions with the Syrian government over an alleged chemical weapons attack on Wednesday and is following the situation carefully, a UN spokesman said Wednesday.

“Professor Sellstrom is in discussions with the Syrian government on all issues pertaining to the alleged use of chemical weapons, including this most recent reported incident,” a statement read out by Spokesman Eduardo del Buey said.

Ban was shocked by the report of the alleged attack, the statement said.