The attacker was identified as Vedat Acar, a 24-year-old from the eastern Van province who joined the PKK six years ago, the report said.

The PKK has denied responsibility for the attack, in which 15 officers and 17 civilians were injured as the attacker attempted to board a police bus.

The PKK said on Monday said it was prolonging a unilateral truce, first declared in August, which had expired on the day of the blast.

Police had arrested seven suspects in Istanbul, all of whom were PKK members, the report said.

NTV news channel reported that the bomber had entered Turkey from northern Iraq three months ago, via the border-crossing at Habur in the southeast of the country.

PKK rebels operate training camps in the mountains of northern Iraq, from where they have launched repeated attacks against Turkish security forces mostly in the Kurdish-majority southeast.

A top PKK commander said last week the group would no longer target civilians and wanted to extend the truce indefinitely if Ankara makes reciprocal gestures.

Prime Minister Recep Tayyip Erdogan's government has launched a cautious bid for a dialogue with the Kurds, seeking to cajole the PKK into laying down arms.

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