The video clip of an activist being buried alive was posted by sympathisers to the uprising

Alleged video footage of a Syrian activist being buried alive for supplying video clips to newspapers has surfaced online.

The clip, which could not be independently verified by the Huffington Post UK, shows a blindfolded man buried up to his neck in dirt and rocks, pleading for his life.

Armed guards point weapons at his face, while others pick up shovels and bury him above his head.

'There is no god but God,' the man says, in Arabic. 'There is no god but Bashar,' the loyalists reportedly reply.

In the clip, which is extremely disturbing, the man is covered by the rocks and eventually falls silent.

Meanwhile in the city of Hama a bomb attack on a residential building left at least 70 people dead.

Activists claimed the bombing was carried out by government forces, while state media reported militants had accidentally exploded a makeshift device.

Reports from the scene said that the scale of the destruction would be impossible to achieve with conventional bombs.

The attack in the Masha at-Tayyar district of Hama killed at least 13 children and 15 woman, according to a report quoted by the BBC.

There are currently two UN observers in the city, which has a population of more than 460,000 people.

More than 100 people have been killed in Hama in recent days as a supposed ceasefire continues to unravel.

The peace plan coordinated by international envoy Kofi Annan is currently being monitored by an advance team of UN officials ahead of the deployment of a larger peacekeeping force.

Annan on Tuesday condemned the "totally unacceptable and reprehensible" reports that Syrian forces had re-entered Hama, in contradiction of the terms of the ceasefire.

Meanwhile the French government has said the UN should consider the use of force in Syria is the ceasefire falls apart completely.

More than 9,000 people have been killed in Syria since the start of the uprising in March 2011, according to the UN.