The Britain-based Syrian Observatory for Human Rights said 30 people were wounded by air strikes and artillery fire but that the intensity of the bombardment targeting the Eastern Ghouta region near the capital had lessened from Friday night.

"There have (since) been practically no air raids and even artillery fire is less intense," Observatory head Rami Abdel Rahman told AFP, although warplanes had struck areas near Douma, the region's main town.

Rebel shelling triggered a fire at a power plant in the capital, the official news agency SANA said.

The sharp drop in violence came as regime forces and their allies were targeted by major Israeli air raids Saturday after an Israeli warplane crashed after being fired on by Syrian air defences.

Five straight days of bombardment by regime warplanes and artillery from Monday to Friday killed more than 240 civilians, including 60 children, and wounded 775 people, the Observatory said.

The offensive had trapped thousands of families in makeshift bomb shelters and overwhelmed rescue workers, but on Saturday life in Eastern Ghouta appeared to be returning to normal in some areas.

Some shops reopened in Douma, Erbin and Hammuriyeh, and residents were seen sweeping up rubble outside their homes as others salvaged what they could from destroyed houses, AFP correspondents said.

The UN Security Council is considering a draft resolution demanding a 30-day ceasefire in Syria to allow for urgent deliveries of humanitarian aid, according to the text seen by AFP on Friday.

Sweden and Kuwait presented the measure that would also demand an immediate end to sieges, including in Eastern Ghouta.

Negotiations on the proposed measure are to begin on Monday, and diplomats said it could quickly come to a vote at the council.

Western powers have expressed alarm over the government's campaign against rebel-held Eastern Ghouta, where 400,000 people have been besieged since 2013.

UN human rights chief Zeid Ra'ad Al Hussein on Saturday accused Syrian forces of carrying out "no-holds-barred" military offensives.

He denounced "wave after wave of deadly air strikes leading to civilian casualties" in Eastern Ghouta and the opposition-controlled northwestern province of Idlib.