State television ran footage of "barrels filled with highly dangerous toxic and chemical agents" as well as gas masks, saying they were only a small sample of what had been unearthed in overrunning rebel positions.
The rebels "used these agents to try to halt the advance of the army," it said.
"An army unit is surrounding a sector of Jobar where terrorists used chemical weapons," said the state broadcaster, adding that soldiers who tried to enter the neighbourhood had "suffocated".
The state broadcaster said several soldiers had suffered poison gas inhalation and some were in critical condition.
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The Syrian Observatory for Human Rights said the government carried out four air raids today on areas near Jobar, where soldiers and rebels fighters were locked in fierce clashes.
The state broadcaster also said Saudi Arabia and Qatar, which both openly support the 29-month-old revolt against President Bashar al-Assad, had supplied rebels with the gas masks and medication.
In a sweep of Jobar, "the army found barrels marked 'made in Saudi Arabia' and gas masks, " a correspondent for the channel reported, adding that medicine for poison gas inhalation was also found, with the brand of an unnamed German-Qatari firm.
The UN disarmament envoy, Under Secretary General Angela Kane, was in Damascus today after the opposition accused Assad's forces of killing more than 1,300 people in gas attacks Wednesday southwest and east of the capital.
Syria has denied the charges but has yet to say if it will allow a team of UN chemical weapons inspectors -- already on the ground since Sunday to probe three other sites -- to investigate the latest allegations.