Syrian fighter jets have bombarded residential areas in the northwest province of Idlib, killing at least 16 people, including seven children and five women, an activist group say.

"The number of people killed in the air strike in the village of Bara in Jabal al-Zawiya has risen to at least 16," the Syrian Observatory for Human Rights said on Sunday.

Syrian warplanes had earlier shelled eastern suburbs of the capital, Damascus, activists say, continuing air raids despite an internationally brokered ceasefire supposed to take hold two days ago.

Warplanes reportedly hit the adjacent suburbs of Zamalka, Arbeen, Harasta and Zamalka on Sunday, where government forces are trying to root out rebels.

Videos posted online purporting to show the aftermath showed huge plumes of smoke billowing over rooftops.

A statement by the Harasta Media Office, an activists' organisation, said electricity, water and communications had
been cut and dozens of wounded at the Harasta National Hospital had been moved as the bombardment closed in.

Activists also reported fighting in the nearby suburb of Douma, where rebels have been attacking roadblocks, and clashes in Qadam district.

Damascus suburbs have played a major role in the 19-month-old revolt against President Bashar al-Assad, both in terms of peaceful protests and armed resistance.

Eid truce bid

Joint UN-Arab League envoy Lakhdar Brahimi had brokered a ceasefire that was to begin on Friday, the first day of Eid al-Adha.

Regime forces and the rebels had both agreed to a call by Brahimi to lay down their arms for the four-day Muslim holiday, with both reserving the right to respond to attacks.

Spotlight In-depth coverage of escalating violence across Syria

But fierce fighting erupted after a short lull in fighting, with the rival sides accusing each other of breaching the ceasefire.

State news agency SANA said "armed terrorist groups" had attacked checkpoints and planted explosive devices in several cities.

While violence flared in Damascus on Sunday, shelling and clashes were also reported in the eastern Deir al-Zor province.

Fighting was also reported near Maaret al-Numan, a town along the Aleppo-Damascus highway that rebels seized earlier this month.

Opposition fighters have also besieged a nearby military base and repeatedly attacked government supply convoys heading there.

Reports of violence cannot be independently verified as most journalists have been barred from entering the country legally.

The opposition says an estimated 32,000 people have been killed since the uprising began in March last year. Hundreds of thousands of people have fled to neighbouring countries.