Fujimori virtually wiped out Peru's rebel groups

Rebels from Shining Path and the Tupac Amaru Revolutionary Movement (MRTA) are demanding new civilian and prisoner rights.

The authorities have stepped up security measures at prisons across Peru, rejecting "any type of pressure or blackmail" from the inmates.

But a prisoner who identified himself as "Hugo" called AFP news agency to say hundreds more would join the hunger strike in solidarity with Guzman.

There are some 2,800 imprisoned rebels in Peru, most of them captured during disgraced former President Alberto Fujimori's 10-year rule.

'Unfair trial'

Many of them were tried by hooded judges in military courts.

Guzman, who is only taking liquids, says he did not receive a fair trial when he was sentenced to life in 1992 for treason and terrorism.

He launched a nine-day hunger strike in January, ending it after Peru's ombudsman said his demands would be presented to interim President Valentin Paniagua.

The MRTA is best-known for the Japanese embassy siege

On Thursday, the ombudsman, Walter Alban, urged the inmates to maintain the peace.

Mr Alban said prison conditions for those convicted of terrorism had been improved to respect inmates' human rights.

Under Guzman's leadership, the Maoist Shining Path movement began its campaign to install a communist state in 1980.

The MRTA is best known for the 126-day siege of the Japanese ambassador's residence in Lima in 1996.

The guerrilla conflict left some 30,000 dead and caused more than $25bn in damage.

Both rebel groups were mostly destroyed under Mr Fujimori's rule, and have only been blamed for sporadic attacks in the past few years.