Some 1,000 people have been killed in the past five days alone, the Britain-based watchdog said.

"This is all-out war -- there is no other way to describe the violence in Syria," Observatory director Rami Abdel Rahman told AFP.

At least 23,630 civilians have been killed, along with 8,211 soldiers and 1,241 army defectors who joined the insurgency against President Bashar al-Assad.

The Observatory's civilian toll also includes non-military defectors who took up arms against the regime.

"If the conflict ends and a full assessment are carried out on the ground, the toll may well turn out to be higher," Abdel Rahman said.

His group's tallies do not count the many unidentified victims of the bloody conflict, nor do they include thousands of people missing and thought to be in detention.

They also exclude thousands of pro-regime militiamen, Abdel Rahman said.

The Observatory relies on a network of activists, lawyers and medics on the ground inside Syria for its information.