The suspected assailant in the January 3 car bomb attack in Diyarbakir confessed to a plan for a second blast and led the police to the place the bomb was hidden, Governor Huseyin Avni Mutlu told a news conference.

The police seized the remote-control bomb, made of 800 grams of plastic explosives attached to two rockets, as well as another three kilogrammes of explosives, detonators, a hand grenade, a gun, fake ID cards and printed Kurdistan Workers' Party (PKK) material.

"A fresh disaster was prevented," Mutlu said as officials displayed the seized items to the media.

Mutlu described the suspected bomber as a PKK militant who was trained "in bomb-making, assassinations and sabotages" in rebel camps in neighbouring northern Iraq and tasked with carrying out high-profile attacks in Turkey.

The 23-year-old man was to appear before a judge later Friday, along with seven other people suspected of having helped him in the attack.

The judge was to question the suspects and decide whether to formally charge them.

Police have said the alleged bomber confessed in his interrogation to having detonated the bomb on PKK orders in the wake of Turkish air raids on the rebel group's camps in Iraq in December.

The explosives-laden car was set off by remote control in central Diyarbakir on January 3, targeting a military vehicle passing by with some 50 soldiers on board.

The blast claimed six lives, including five teenagers attending private classes at a nearby building, and wounded 67 people, among them some 30 soldiers.

The PKK, listed as a terrorist group by Ankara and much of the international community, apologised for the attack Tuesday and put the blame on Kurdish militants acting without the approval of the leadership.

Army chief Yasar Buyukanit described the blast as a sign of "panic" in PKK ranks following the Turkish strikes on rebel bases in northern Iraq, where the group has long taken refuge.

The military has confirmed three air raids conducted with US intelligence assistance against the PKK in Iraq since December 16 in which it said at least 150 rebels were killed and more than 200 PKK positions destroyed.

Iraqi officials said Friday Turkish forces shelled areas across the border in northern Iraq. There was no immediate word about casualties or damage.

The PKK has waged a bloody campaign for self-rule in mainly Kurdish southeast Turkey since 1984. The conflict has claimed more than 37,000 lives.