Syrian government forces on Wednesday attacked a rebel-held town southwest of Damascus with artillery fire and helicopters dropped barrel bombs as opposition groups accused the government of using poison gas in an assault there the previous night.
Five people, among them one civilian, died of suffocation following a missile attack Tuesday night, according to a media activist based in the town of Moadamiyeh. He said four missiles were fired from the nearby Mezze Air Base and struck at the same time as a barrel bomb attack, adding to the confusion. No other people have since been reported killed.
Amateur videos from a town clinic, made available Wednesday, show medics intubating apparently unconscious patients. They did not appear to have suffered traumatic injuries.
Washington could not confirm the attacks.
"The initial reports appear to be credible but we cannot confirm them," said a U.S. official, speaking on condition of anonymity because he was not authorized to speak publicly about the matter. He added that it will be up to U.N. experts to validate the claims.
The claim of a poison gas attack could not be independently verified. It was also reported by the Local Coordination Committees group and the main Western-backed Syrian National Coalition opposition group.
The activist in Moadamiyeh, who identifies himself by his first name, Ahmad, said helicopters dropped more than 40 barrel bombs on the town and its surrounding areas Wednesday.
A video shared on social media shows a helicopter dropping four barrels in quick succession over what is purported to be the town area, while another shows a tank advancing on a scorched plain outside the town.
"The goal is to sever the road between Moamadiyeh and Daraya, to completely besiege and separate the two areas," said Ahmad. He said the assault continued into the evening.
The two towns have been under siege by government forces since 2013. Government and opposition forces struck a truce to allow food into Moadamiyeh that December, but it has been broken many times. The latest bout of fighting began last week.
Moadamiyeh was the site of a 2013 chemical attack on rebel-held areas outside Damascus that killed hundreds of people.