Regime and Russian air strikes on a rebel-held enclave near the Syrian capital killed at least 17 civilians on Saturday, a war monitor said.

Eastern Ghouta, one of the last remaining opposition strongholds in the country, is the target of near-daily air raids.

The Syrian Observatory for Human Rights said Saturday's deadliest strikes had hit the Hammuriyeh district, killing 12 civilians including two children.

An AFP reporter in Hammuriyeh saw residential buildings with their facades blown open, collapsing into streets strewn with rubble.

Residents including members of the White Helmets rescue group rushed to rescue the wounded.

Running past a burning car, one man held a crying boy in his arms, while another carried the apparently lifeless body of a child through the streets.

Observatory head Rami Abdel Rahman said Syrian and Russian aircraft had "continued their intense bombardment of Eastern Ghouta, targeting several residential areas".

He said those killed also included two people in the district of Madira and three in Erbin, adding that 35 people were also wounded in the three areas.

The Britain-based monitor relies on a network of sources inside Syria and says it determines whose planes carry out raids according to type, location, flight patterns and munitions used.

At the start of the week, a coalition of rebels and jihadists including a former Al-Qaeda affiliate surrounded the only regime base in Eastern Ghouta, which lies east of Damascus and has been under a crippling regime siege since 2013.

The blockade has caused serious food and medicine shortages for the enclave's estimated 400,000 inhabitants.

More than 340,000 people have been killed in Syria and millions displaced since the conflict began in March 2011 with anti-government protests.