The discovery came after the government forces surrounded a sector of militant-held district of Jobar on Saturday.
"Army heroes are entering the tunnels of the terrorists and saw chemical agents," Syria television said, adding, "In some cases, soldiers are suffocating while entering Jobar.”
It added that ambulances arrived in the region to rescue the people who were suffocating in Jobar and the area is now controlled by Syrian army forces.
The Syrian government also stated that the foreign-backed militants had carried out the recent chemical attack in Damascus suburbs of Ain Tarma, Zamalka and Jobar.
On Wednesday, Syrian opposition claimed that hundreds were killed in a government chemical attack on militants’ strongholds in Damascus suburbs of Ain Tarma, Zamalka and Jobar before dawn.
The Syrian army has vehemently denied allegations that it used chemical weapons against Takfiri militants in the suburbs of the Ghouta region, saying the accusations were fabricated to distract the visiting team of UN chemical weapons experts and to cover up militants’ losses.
Meanwhile, UN Under-Secretary-General Angela Kane arrived in Damascus on Saturday for talks aimed at establishing an investigation into the Wednesday’s attack.
In a related development, Russian Foreign Ministry on Friday accused Syria’s opposition of preventing an objective probe into the alleged attack.
US Defense Secretary Chuck Hagel, however, said his commanders have prepared a range of options for President Barack Obama if he chooses to go for military action against Syria.
"The Defense Department has a responsibility to provide the president with options for contingencies, and that requires positioning our forces, positioning our assets, to be able to carry out different options - whatever options the president might choose," he said.
Syria has been gripped by a deadly unrest since March 2011.
The United Nations says more than 100,000 people have been killed and a total of 7.8 million others displaced since the outbreak of the violence.
According to reports, Western powers and their regional allies -- especially Qatar, Saudi Arabia, and Turkey -- are supporting the militants operating inside Syria.
HH/HH