Rebels of the Kurdistan Workers' Party (PKK) fighting for a homeland separate from Ankara attacked the academy in the town of Siirt, they said.

The civilians died as they passed the scene of the hand grenade attack in a car. Two people were also wounded.

While fighting still raged in the area, a powerful bomb rocked the centre of the Turkish capital Ankara on Tuesday, killing three people and injuring at least 15, the interior minister said, as immediate suspicion fell on Kurdish separatists.

Turkish planes have repeatedly bombed PKK bases in northern Iraq since August 17, and more than 100 rebels have been killed in the raids, according to official figures.

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