THE 11-MONTH-OLD UPRISING in Syria has seen its bloodiest episode yet, after Syrian army forces unleashed a three-hour barrage of mortar bombs and artillery shells on the city of Homs.

Local activists say at least 200 people have been killed, while a member of the country’s opposition told Sky News that the death toll had risen to 350.

Women and children were among the victims, Abu Rami Alhomsy said.

“Homs is on fire,” another opposition activist – who did not want to be identified for fear of reprisal - said in a quieter area near the city. ”All sides are attacking each other and the number of casualties is more than anyone can count.”

The government denied the assault and said that corpses shown in amateur videos posted online — bodies that activists said were victims of the assault — were purportedly of people kidnapped by “terrorist armed groups” who filmed them to portray them as victims.

One video showed a chaotic scene as men, with various wounds and gashes, were being tended to or were praying in what appeared to be a makeshift clinic in Khaldiyeh.

Another showed a fire ravage a house in the district, as people desperately tried to put out the blaze with water.

The Syrian Observatory for Human Rights had earlier put the death toll at 217, making it easily the worst bloodshed in the push to end the authoritarian regime of Bashar Assad, who has drawn international criticism for his heavy-handed response to the protests.

Homs, Syria’s third largest city, is a hotbed of dissent to Assad’s regime and is known to shelter a large number of army defectors known as the Free Syrian Army. The city has seen several crackdowns by security forces but many parts of it remain outside of government control.

The shelling prompted fresh overnight protests at Syrian embassies in the western world, with around 150 Syrians assembling in London to smash the windows of the local embassy there.

The Guardian reported that Syrians outside the Washington embassy changed, “Syria soon will be free”.

The disruption comes as the UN’s Security Council prepares to vote on a draft resolution condemning Syria’s violent crackdown. Russia, which vetoed a previous motion, has threatened to do so again.

Moscow’s foreign minister Sergey Lavrov said Russia had submitted amendments, hoping that “bias will not prevail over common sense”, and warned that an attempt to push the motion to a vote would lead to “scandal”.

Additional reporting by AP