The bodies, which were still holding weapons, were found during a search near Diyarbakir, the sources said.

The seven did not appear to have died during fighting, the sources said, suggesting they may have been killed in an internal dispute or in a PKK execution. An inquiry has been launched.

The PKK, which is considered a terrorist organisation by the Turkish government, the European Union and the United States, announced a unilateral ceasefire in October 2006.

Ankara rejected it but the fighting, which has seen more than 37,000 people killed since the PKK's armed campaign began in 1984, has reduced since then.