Syria's air force on Monday carried out several air strikes on rebel enclaves in and around Damascus, while fresh clashes between troops and rebels raged to the east of the capital, a monitoring group said.

"At least one civilian was killed in an air strike on Qaboon" in northeast Damascus, the Syrian Observatory for Human Rights said, "while regime troops pounded the district of Jubar" in the east.

Amateur video distributed by the Syrian Revolution General Commission (SRGC), a network of activists on the ground, showed a cloud of grey smoke rising after the air raid.

The regime also used warplanes to bombard the rebel-held towns of Yabroud, Douma and Harasta east of Damascus, as well as Sbeineh southwest of the capital, said the Observatory.

Meanwhile, "fierce clashes raged on the edges of Jubar (in eastern Damascus), near Abbasiyeen square," said the group.

Rebels view the square as a strategic target because it lies well within the confines of the capital, the regime's main bastion of power.

The SRGC, meanwhile, reported the army's use of heavy artillery fire on Yarmuk in southern Damascus, with tanks also striking other rebel enclaves nearby.

Violence rages daily in southern Damascus, with rebels holding the outer edges of several districts, while the regime tries to push them out.

Elsewhere in Syria, warplanes also hit targets in the northeastern city of Raqa as well as an area near the regime-held Base 17 in the same province.

Raqa's provincial capital fell into rebel hands in early March, and insurgents have since been fighting to gain control of Base 17, one of the army's few remaining bastions in the province.

In coastal Syria, "the army launched a massive operation... in the north of Latakia province", near the Turkish border, attacking rebel-held villages, said pro-regime daily Al-Watan.

And in the northwest, the Observatory reported fierce clashes pitting rebels against troops in Idlib while the army tried to send in supplies to soldiers holed up in besieged Wadi Deif and Hamidiyeh bases.

In the same province, the army took control of two hills overlooking insurgent-held villages, said the watchdog.

Later in the day, fierce clashes broke out near key the Idlib town of Maaret al-Numan, which rebels seized last October.

According to a preliminary toll for Monday, at least 22 people were killed in violence across Syria, said the Observatory, which relies on a broad network of activists, doctors and lawyers for its reports.