The UN General Assembly yesterday condemned Syrian President Bashar al-Assad’s forces and praised the opposition, but a decline in support for the Gulf Arab-drafted resolution suggested growing uneasiness about Syria’s fractious rebels.

While the non-binding text has no legal force, resolutions of the 193-nation assembly can carry significant moral and political weight. There were 107 votes in favour, 12 against and 59 abstentions – a drop in support compared with a resolution condemning the Syrian government that passed last year with 133 votes in favour, 12 against and 31 abstentions.

Russia, a close ally of Assad, strongly opposed the resolution drafted by Qatar. Diplomats said the Russian delegation wrote to all UN members urging them to oppose the resolution. Moscow has complained that it undermines US-Russian efforts to organise a peace conference that would include Assad’s government and rebels, a meeting that US Secretary of State John Kerry said would likely take place next month.

Meanwhile as the Syrian conflict rumbles on, the prevalence of camera phones and internet access has allowed hundreds of gruesome war crimes to be broadcast, spreading hatred and fear. Such macabre scenes are defining the war that is spilling across Syria’s borders and making reconciliation an ever more distant prospect.

A few days ago Syrian soldiers were recorded slowly stabbing a man to death, puncturing his back dozens of times. A rebel commander went on video biting an organ ripped out of an enemy combatant while a young boy was filmed hacking the head off a prisoner.

Brutality has been used as a tool since the revolt began two years ago, when videos emerged of government soldiers torturing pro-democracy protesters. In response, the opposition took up arms and now fighters from both sides are filming themselves committing atrocities.

Ghoulish footage of violence is not filmed surreptitiously, but with pride by the assailants who often speak to camera.

Rebel commander Abu Sakkar, known to journalists and revered by many rebels, was shown in a video on Sunday cutting organs out of a dead soldier, addressing the camera as he ripped the flesh: “I swear to God we will eat your hearts and your livers,” he warned President Bashar al-Assad’s forces as his men cheered.

Sakkar was a founding member of the Farouq Brigade, one of the main rebel units in Syria, but has since formed his own battalion as the opposition fragments. In the mosaic of hundreds of opposition groups, Sakkar’s men are seen as neither secular nor hardline Islamists, but as some of the hardiest fighters.

Another picture posted online shows a rebel holding the severed head of a man, supposedly an Assad loyalist, over a barbecue as if to cook it. The fighter smiles and poses confidently, gripping a tuft of hair.

Reinoud Leenders, an associate professor in the war studies department of King’s College London, says that these brutal displays are used as a tool of war by both sides.

“It’s the ultimate expression of disrespect and dehumanising your opponent,” he said.