Chemical weapons attacks have killed hundreds on the outskirts of Damascus, Syrian opposition activists say. Rockets with toxic agents were launched at the suburbs of the Ghouta region early on Wednesday as part of a major bombardment on rebel forces, they say. The Syrian army says the accusations have been fabricated to cover up rebel losses. The main opposition alliance said that more than 1,000 people were killed by the attacks. Activist networks also reported death tolls in the hundreds, but these could not be independently confirmed. It is also not clear how many died in the bombardment of the sites and how many deaths were due to any exposure to toxic substances. Video footage showed dozens of bodies with no visible signs of injuries, including small children, laid out on the floor of a clinic. Ghazwan Bwidany, a doctor treating the injured, told the BBC the main symptom, especially among children, was suffocation, as well as salivating and blurred vision. "There are some kind of symptoms that tell us that this is phosphorus, which is a chemical weapon. It may be sarin, most probably it's sarin. "We don't have the capability to treat all this number of people," he said. "We're putting them in mosques, in schools. We are lacking medical supplies now, especially atropine, which is the antidote for chemical weapons." In a statement, the army described the accusations of chemical weapons use as grave, and stressed the military's right to fight what it described as terrorism in Syria. It accused the opposition of fabricating the accusations to divert attention from the huge losses its forces had suffered recently. The US, UK and France have requested an urgent United Nations Security Council meeting on Wednesday. UK Foreign Secretary William Hague and French President Francois Hollande called for UN inspectors to be allowed access to the area. If confirmed, the attacks would mark a "shocking escalation in the use of chemical weapons in Syria", Mr Hague said. The Arab League and European Union echoed the call for the inspectors to go to the site. "The EU reiterates that any use of chemical weapons, by any side in Syria, would be totally unacceptable," said a spokesperson for EU foreign affairs head Catherine Ashton. The Russian foreign ministry noted that the reports had emerged just as a UN chemical weapons inspection team had arrived in Syria, saying that "this makes us think that we are once again dealing with a premeditated provocation". 'Convulsions' The attack took place as part of a heavy government bombardment of the region surrounding Damascus, where government forces have been trying to drive out rebel forces. Casualties were reported in the areas of Irbin, Duma and Muadhamiya among others, activists said. Footage uploaded to YouTube from the scene by activists shows many people being treated in makeshift hospitals. The videos show victims, including many children, having convulsions. Others are apparently immobile and have difficulty breathing. The BBC has not been able to authenticate the footage fully, but based on additional checks made, it is believed to be genuine. "Many of the casualties are women and children. They arrived with their pupils dilated, cold limbs and foam in their mouths," a nurse at a Duma medical facility, Bayan Baker, told Reuters. The videos show victims, including many children, having convulsions. Others are apparently immobile and have difficulty breathing. The BBC has not been able to authenticate the footage fully, but based on additional checks made, it is believed to be genuine. "Many of the casualties are women and children. They arrived with their pupils dilated, cold limbs and foam in their mouths," a nurse at a Duma medical facility, Bayan Baker, told Reuters.