A raid by Syrian security forces on a riot-hit prison in the central city of Hama has failed to end a mutiny involving around 800 inmates, a monitor said Saturday.

Ten guards were taken hostage after the violence broke out on Monday following an attempt to transfer detainees to another prison near Damascus where numerous executions of inmates have been reported.

Activists say most of the prisoners at the Hama jail are political detainees linked to the opposition.  

Inmates “continued their mutiny on Saturday after the assault failed,” said the Syrian Observatory for Human Rights, a British-based monitor.

“Tensions remained high,” Observatory chief Rami Abdel Rahman said, “and security forces remained inside the prison but outside the cells.”

Security forces had stormed the prison on Friday firing bullets, rubber bullets and tear gas, according to the Observatory.

They also arrested relatives of prisoners gathered outside the building concerned about their fate, it said.

The raid led to injuries among several inmates and “cases of fainting and choking” from the tear gas, the monitor reported.  

Video footage posted on social networks showed a corridor filled with flames and smoke as a voice is heard giving the date as May 6 and the location as the central prison in Hama.

The sound of bursting tear gas grenades can be heard as inmates chant “Allahu Akbar!” (God is greatest) while others are heard coughing. It was not possible to verify the authenticity of the footage.

Syrian activist group the Local Coordination Committees has said inmates are protesting against death sentences handed to dozens of prisoners and also against conditions inside the jail.

Water and power supplies remained cut off inside the jail on Saturday, according to the Observatory, which said the authorities had released 46 prisoners since the protest began.  

Syria’s main opposition group involved in peace talks on Friday called on international organisations “to intervene to prevent an imminent massacre” of prisoners.

The High Negotiations Committee urged the international community to “shoulder its responsibilities” and stop the regime from carrying out “reprisals against the detainees.”

France warned of the risk of “deadly reprisals by the regime” and urged Damascus’s allies to exert pressure “to avoid another massacre in Syria.”

More than 200,000 people have spent time in regime prisons since 2011, according to the Observatory, which relies on a network of sources inside Syria for its information.

Tens of thousands of political detainees are reported to have died of torture, of which the Observatory says it has verified 14,000 cases.

More than 270,000 people have died since the Syrian conflict started with the brutal repression of anti-government protests in 2011.

AFP contributed this report.