The court in Diyarbakir, the largest city in the Kurdish-majority southeast, charged Colonel Cemal Temizoz with belonging to an armed organisation and inciting murder, the official told AFP on condition of anonymity.

The colonel became the third suspect to be charged this month as part of a probe into allegations that supporters of the outlawed Kurdistan Workers' Party (PKK) were murdered and buried in "death pits" in the southeast in the 1990s, at the peak of the group's separatist campaign against the government.

The colonel, who had been questioned since Monday, was the head of a paramilitary police force stationed in Cizre, Sirnak province, in 1993-1996.

Recent digs in the area turned up 20 fragments of bone and pieces of tissue in what the media have dubbed "death pits".

The two other suspects awaiting trial are the former mayor of Cizre, Kamil Atak, and his son Temel, who were at the time members of the "village guard" -- a Kurdish militia armed by the government to back the army against the PKK.

They allegedly organised the abduction and killing of PKK sympathizers, within the knowledge and under the protection of the colonel.

The investigation was launched in February after media published accounts of the alleged murders by a PKK militant who defected from the group and became an informer for the security forces.

An unidentified witness told prosecutors that Atak had handed over several people suspected of aiding the PKK to members of another outlawed group, the Islamist Turkish Hizbullah, who in turn killed them.

The Turkish Hizbullah, which has no known links to its Lebanese namesake, was set up in the early 1990s as a reaction to the PKK and is believed to have been used by Turkish authorities against the rebels.

The PKK took up arms for Kurdish self-rule in 1984, triggering a conflict with the Turkish state that has left 44,000 dead, displaced thousands and led to allegations of gross human rights violations by both sides.

Over the past 10 years the bodies of four missing people have been exhumed in the region, the most recent in 2005 by a roadside.