The Syrian government denied claims Friday by opposition activists that the government used poison gas in an attack the previous day on the rebel-held town of Nabek, north of the capital.
Amer al-Qalamouni, an activist, said shells used in the bombardment produced a white, yellowish smoke and a strange odor. He said seven people were exhibiting symptoms consistent with gas attacks, such as foaming at the mouth.
The Syrian Revolution Coordinators Union also accused Assad's forces of using poison gas in Thursday’s shelling of Nabek.
"We have documented nine casualties from poison gas used by the regime in neighborhoods of Nabak," the group said on its Facebook page.
CBS News has found no videos from Nabek showing clear evidence of a chemical weapons attack on social media, unlike in other instances where many victims were shown foaming at the mouth or convulsing.
The government swiftly denied the reports.
A Syrian government official told CBS News' George Baghdadi on Friday the claims were, "completely untrue," and dismissed them as an "attempt to vindicate the losses of terrorists in the face of Syrian Arab Army."
Fighting around Nabek has been intense in recent weeks, with Syrian warplanes repeatedly bombing the area as Islamic militant factions of the opposition try to cut the vital supply route used by the regime to get materials to forces in the capital.
The opposition has accused the government of using chemical weapons on several occasions over the course of Syria's nearly three-year-old conflict.
After the U.S. threatened to carry out punitive missile strikes against the government, Assad agreed to give up his chemical arsenal, and international experts are currently overseeing the program's destruction as part of a deal brokered by the U.S. and Russia.