Prosecutors ordered the dig in Derecik, Hakkari province, after receiving a letter from a former soldier who claimed to have witnessed the killing of the 12 men there, the sources said.

It was the latest in a series of recent excavations seeking to shed light on allegations that a number of Kurds who went missing in the 1990s, at the height of a bloody insurgency in the southeast, became the victims of summary killings by security forces.

The 12 belonged to the so-called village guard, a local Kurdish militia armed and paid by the government to support the army against militants of the separatist Kurdistan Workers' Party (PKK).

Relatives say the men had been accused of double-play -- aiding and abetting PKK militants -- before they saw them for the last time, being led away by soldiers.

In the first court case to emerge from recent digs, a colonel and six other people were charged last week over the summary killing of 20 Kurds in the 1990s, all risking the life sentence.

The colonel is accused of having set up a rogue gang that detained, questioned and killed people for helping the PKK or to settle personal accounts.

The PKK, listed as a terrorist group by Ankara and much of the international community, took up arms for Kurdish self-rule in the southeast in 1984, sparking a conflict that has claimed about 45,000 lives.

The conflict has displaced thousands and led to allegations of gross human rights violations by both sides.