A Syrian rebel leader says he ate the heart of a government soldier as revenge for atrocities committed by the government.

Gruesome video footage, which has sparked international condemnation, shows Khalid al-Hamad taking a bite from the heart.

US-based group Human Rights Watch says he then urges his followers to do the same to Alawites - the Muslim sect that Syrian president Bashar al-Assad belongs to.

Time magazine says it has talked by Skype with Hamad.

It says Hamad claimed he was driven to the gruesome acts by footage on the dead soldier's mobile phone, showing him "humiliating" a naked woman and her two daughters.

The US magazine says Hamad described participating in other acts of mutilating regime forces, including militiamen known as shabiha.

"Hopefully we will slaughter all of them," he told the magazine, referring to Alawites.

"They were the ones who killed our children in Baba Amr and raped our women," he said, referring to a neighbourhood of the central city of Homs.

"We didn't start it, they started it.

"Our slogan is an eye for an eye and a tooth for a tooth."

'Atrocious act'

UN Human Rights Commissioner Navi Pillay calls it a "truly atrocious act".

She has urged the UN Security Council - where Russia and the US are at loggerheads - to refer the conflict to the International Criminal Court so all sides guilty of war crimes can be prosecuted.

"While it is not yet possible to fully authenticate the video, I urge the armed opposition groups in Syria must do everything in their power to halt such gross crimes," she said.

"They must investigate this incident along with other alleged very serious violations by opposition fighters, including acts of torture and a succession of apparent summary executions and extra-judicial killings."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 2 minutes 50 seconds 2 m 50 s Correspondent Matt Brown reports on the reaction to the footage Download 1.3 MB

The National Coalition, the country's main opposition group, issued a statement saying it "strongly condemns" the act.

It says the rebel soldier will be put on trial.

The United States has denounced the actions of the rebel but insists it was the act of a lone brutal individual.

"We're appalled by this video and we've been very clear that all sides in this conflict must abide by international humanitarian law," State Department spokesman Patrick Ventrell told reporters.

He says Washington has "raised this gruesome act in our recent conversations with leaders of the Supreme Military Council, who assured us that they do not support such actions and that this is not representative of the vast majority of the armed opposition".

He also says the rebel had been "previously ejected" from his unit "because of his history of brutality".

Toll rises

The pro-opposition Syrian Observatory for Human Rights has revised its death toll in the country's civil war from 82,000 two days ago, to more than 94,000.

It says the updated figure comes after receiving new information from regime-controlled areas inside Syria.

Meanwhile, Russian president Vladimir Putin is warning against any moves that could "shake" or further destabilise the conflict in Syria.

Mr Putin issued the warning in Moscow after talks with visiting Israeli prime minister Benjamin Netanyahu.

Israel launched a series of air strikes against regime targets in Syria last week, prompting both concern and support from the international community.

Mr Netanyahu has also expressed concerns about Russian plans to sell an advanced anti-aircraft system to the Syrian government.

ABC/wires