A Turkish prisoner who has been on hunger strike for the past 18 months in protest against the country's prisons has died.

Turkish authorities say the old prisons were "training camps" for militants

Serdar Karabulut, 32-years-old and a member of the outlawed left-wing group the People's Revolutionary Liberation Party-Front, or DHKP-C, died in Ankara hospital, a prisoners' rights group said.

He was moved from the prison - where he was serving a 30-year sentence for being a member of DHKP-C - to hospital after his condition deteriorated.

His death brings the total number of prisoners, and their supporters, who have starved to death since the hunger strike began in October 2000 to 58.

Exploitation claims

The hunger strikers are protesting over new prisons which they say would isolate them from their comrades.

The strikers refuse all solid food, but take vitamins and sugared or salted water in order to lengthen their fasts.

At present prisoners are held in cells which can accommodate up to 100 people.

But the controversial new 'F-type' prisons Turkish authorities have cells which instead accommodate only two or three prisoners.

The prisoners, mostly members of small left-wing groups the Turkish Government accuses of terrorism, claim the newly-designed jails leave them vulnerable to exploitation or abuse.

Numbers dwindling

However the government claims that the old prisons with communal dormitories had become "training camps" for the left-wing groups, with riots and hostage-taking incidents common.

They also insist that the new prisons conformed with United Nations and European Union guidelines and that, far from crushing the prisoners, they would allow them to develop their identity away from the ideological constraints of their colleagues.

At one point up to 750 inmates and their supporters were on hunger strike, however this number appears to have dwindled to around 20 in recent months, the French news agency AFP reported.