Syrian government forces launched air raids over rebel-held areas around the capital Damascus and districts of Aleppo, with deaths and injuries reported.
Amateur video showed government warplanes overflying rebel-held suburbs of Damascus, amid reports of bombing raids Sunday on the suburbs of Douma and Daraya. Witnesses also reported air raids and numerous casualties in and around Aleppo, the country's largest city.
Arabiya TV showed live video of the aftermath of the bombing raid over Douma. At least half a dozen buildings appeared to have been gutted, with chunks of concrete and other rubble falling into the street as residents ran to get away.
A man who claimed to be an eyewitness told Arabiya TV that government planes and helicopters had hit a market, causing numerous casualties. But it was not clear from the video if there was a market in the area that was hit.
Government shelling against rebel-held districts of Aleppo, along with air raids Sunday, killed more than two dozen people according to Arab TV channels. The government raids followed rebel attacks Saturday on key government buildings, including an intelligence headquarters.
Meanwhile, the Syrian government and the rebels traded accusations over allegations poison gas was used Saturday in the town of Kfar Zita, outside Hama, and Friday in a rebel-held suburb of Damascus.
Details of the reported incidents remain sketchy and several allegations appear to have little basis in fact.