The defendants were serving in a paramilitary force that transferred political prisoners in 2000 from Istanbul's Bayrampasa prison to new, maximum-security prisons to stop frequent rioting.

The inmates were protesting the move from large wards to smaller cells.

Twenty-six defendants attended Tuesday's opening hearing in Istanbul. They are also accused of attempting to murder 29 other inmates by using excessive force, including lethal quantities of tear gas in small prison cells.