"If the promises given are not kept and an attempt is made to delay... or deceive... we will continue our ongoing operations... until we eliminate the last terrorist," Erdogan told a Ramadan fast-breaking dinner in Istanbul.

He made his threat hours after the PKK declared a ceasefire following a call by its jailed leader Abdullah Ocalan to disband.

The PKK said earlier on Saturday it would comply with Ocalan's call to lay down arms and dissolve, adding: "None of our forces will take armed action unless attacked."

The process started in October when Devlet Bahceli -- the leader of the far-right MHP party and a close ally of Erdogan's -- offered Ocalan an olive branch if he would publicly renounce "terror".

In an address to the relatives of people killed or wounded in PKK attacks, Erdogan assured that there was nothing in the initiative "that would disturb the sacred spirits of our martyrs".

He said Turkey would be the winner, as well as "our children, the guarantee of our bright tomorrows".

The Turkish leader warned, however: "We always keep our iron fist ready in case the hand we extend is left hanging in the air or bitten."

That was an implicit reference to the PKK, listed as a "terror" group by Ankara and its Western allies.