Syria rebels kill intelligence officer, clashes rage: NGO

"Rebel fighters ambushed the military intelligence chief in Jaramana on Monday night, after which he was killed," said the Syrian Observatory for Human Rights.

Jaramana, southeast of Damascus, is home to a majority Christian and Druze population and to pro-regime militia. It has suffered numerous rebel bomb attacks in recent months.

The Observatory said the army on Tuesday renewed shelling on the capital's southern districts and that fresh violence erupted on the outskirts of the capital.

Analysts say President Bashar al-Assad's regime wants to ensure its hold on the capital so it can be in a position to negotiate an end to the nearly 21-month conflict that the Observatory says has killed more than 44,000 people.

Elsewhere in Syria, rebels seized the town of Harem in the northwestern province of Idlib, large swathes of which have slipped out of army hands, said the Britain-based monitoring group.

"Insurgents from several rebel groups have seized total control of the town of Harem, after taking ... the army and pro-regime militia's last bases there," said the Observatory.

Pro-Assad forces surrendered to the rebels after a siege lasting several months, said the watchdog.

Syria's conflict broke out when a peaceful uprising against Assad morphed into a bloody insurgency after the regime unleashed a brutal campaign of repression against dissent.