Human rights groups in Turkey say a hunger strike by 190 prisoners in the eastern city of Erzurum has reached a critical stage. Thirteen of the hunger strikers have refused food for 53 days, and their medical condition is serious. As Chris Morris reports from Ankara, the dispute revolves around the right of prisoners to meet each other on a regular basis:

Most of the prisoners involved in the hunger strike are convicted members of the Kurdish rebel movement, the PKK. Others belong to extreme left-wing groups.

All of them say they're political prisoners, but the Turkish authorities are refusing to grant them any special status. At least seven of the hunger strikers are in critical condition after refusing food for more than fifty days.

They're demanding the right to hold regular meetings with each other, and say the prison authorities must abandon any plans to impose a regime of isolation. The human rights organisation, Amnesty International, says such a regime would violate international laws governing the treatment of prisoners.

Demonstrations in support of the hunger strikers have been taking place on a regular basis in Istanbul, and similar hunger strikes have begun in other prisons. During a nationwide protest against prison conditions in 1996, twelve left-wing prisoners starved themselves to death.