Syrian state television said soldiers found chemical weapons in tunnels that had been used by rebels, deflecting blame for a nerve gas attack that killed hundreds this week and heightened Western calls for foreign intervention.
Opposition accounts that between 500 and well over 1,000 civilians were killed by gas fired by pro-government forces, and video footage of victims' bodies, have stoked demands abroad for a robust, U.S.-led response after 2-1/2 years of international inaction on a conflict that has killed 100,000.
International medical humanitarian organization Doctors Without Borders (MSF) said on Saturday that three hospitals it supports in Damascus reported receiving 3,600 people displaying neurotoxic symptoms within less than three hours on Wednesday.
Of those patients, 355 died, and it had sent 7,000 vials of atropine, a nerve agent toxicity antidote, to the area, it said.
In an attempt to strengthen government denials, state news agency SANA said soldiers "suffered from cases of suffocation" when rebels used chemical weapons against them in the Damascus suburb of Jobar.
It said clashes were still raging in the area but that the army had advanced and found "chemical agents" in rebel tunnels.
State television said rebels used poison gas "as a last resort" after government forces made "big gains" in Jobar.
But footage did not appear to show evidence of chemical weapons. It showed five blue and green plastic drums, normally used to transport oil, lined against a wall in a room, as well as several rusty mortar bombs and grenades.
Next to them were several rolls of tape, rope and some gas canisters, normally used for domestic ovens. Gas masks were seen near some vials labeled "atropine".
The presenter said that these images were proof that the rebels had used chemical weapons but did not say which of the items contained them.
Activists say President Bashar al-Assad's forces fired nerve gas projectiles into Jobar and other suburbs before dawn on Wednesday. Later in the week, activists crossed front lines around Damascus to smuggle out tissue samples from victims.