The victim was identified as Michael Andrew Gibbon, 39, Corrections Canada spokesman Dave Lefebvre said.

'One inmate succumbed to his injuries and was pronounced dead at the institution while a second inmate has been transported to an outside hospital as a result of this assault,' Mr Lefebvre said in a telephone interview.

The incident began in the prison's gym on Saturday night with some inmates breaking windows, Mr Lefebvre said.

'The inmates were threatening toward staff members and later assaulted other inmates,' he said.

It is unclear if Gibbon was attacked or was simply caught up randomly in the violence, Mr Lefebvre said. No staff members were injured.

The institution suffered some damage and was in lockdown on Sunday for clean-up and a search, Mr Lefebvre said.

He said it is too early to determine how many of the institution's inmates were involved.

'It's dozens, not hundreds,' Mr Lefebvre said.

Mountain Institution is a medium security facility operated by the Correctional Service of Canada, 120 kilometres east of Vancouver.

It houses 442 federally sentenced male inmates.

The disturbance is being investigated by Corrections Canada staff while Gibbon's death is being looked at by the Royal Canadian Mounted Police Integrated Homicide Investigation Team.

On March 17, 2007, James Patrick Jones, another man convicted of sex offences involving children, was found dead in his Mountain Institute. -- AP