New strikes pound Syria's Ghouta after alleged gas attack

Fresh air strikes hit rebel-held areas of Syria's Eastern Ghouta today, a monitor said, after more than 80 people were killed in weekend raids including an alleged chemical attack denounced by the United States.

Today's strikes came despite reports of a ceasefire and the potential resumption of talks between Syria's regime and Jaish al-Islam, the last rebel faction in Ghouta.

Allegations of a chlorine gas attack on Saturday were causing widespread international concern, but Syrian state media and regime ally Russia denounced the claims as "fabrications".

Assad's forces renewed their assault on Douma, the last rebel-controlled town in Eastern Ghouta, on Friday after talks over an evacuation of Jaish al-Islam fighters broke down.

The regime has used a fierce military onslaught and two negotiated withdrawals to retake control of 95 percent of Eastern Ghouta, once the main rebel stronghold close to Damascus.

It appeared last week that Douma would follow suit, with the evacuation of hundreds of rebels and their families, but there were reports of divisions among the rebels with hardliners refusing to go.

At least 80 civilians have been killed since Friday after the regime launched fresh air raids, according to the Syrian Observatory for Human Rights, a Britain-based monitor.

The Observatory also reported that dozens of people had suffered breathing problems following the attacks, but could not identify the cause.

The White Helmets, who act as first responders in rebel-held areas of Syria, alleged that regime forces had used "poisonous chlorine gas" in the attacks.

Footage posted by the group online, which was not possible to verify, showed victims including children foaming at the mouth.

There were conflicting reports on the number of dead in the alleged gas attack, with the White Helmets reporting between 40 and 70 killed.

The Observatory said that 11 of those who died at the weekend, including four children, had suffered breathing problems after the raids.

"These reports, if confirmed, are horrifying and demand an immediate response by the international community," US State Department spokeswoman Heather Nauert said in a statement.

"The Assad regime and its backers must be held accountable," she said. "Russia, with its unwavering support for the regime, ultimately bears responsibility for these brutal attacks."