Turkish President Recep Tayyip Erdogan says terrorists had failed in their aim to perpetrate a "big massacre".
Turkish Justice Minister Bekir Bozdag said on Friday that police have detained 18 people in connection with the bomb and gun attack in the coastal city of Izmir. He added that Ankara has "no doubt" that the PKK was responsible.
A police officer and a court employee were killed. Seven others were wounded.
Police are hunting a third suspected assailant who escaped from the scene after the attack near a courthouse.
Thursday's assault was the second attack on a major city in Turkey this week, following the New Year's Day Istanbul nightclub shooting that killed at least 39 people and injured 69. The manhunt also continues for the prime suspect in that attack.
Speaking at a ceremony in Sanliurfa on Friday, President Recep Tayyip Erdogan said attackers had failed in their aim to perpetrate a "big massacre".
"Weapons, bombs, rockets and ammunition confiscated from neutralised terrorists show us the terrorists' aim was a big massacre. Tight measures taken by our security forces resulted in the terrorists being stopped at the security checkpoint before they could reach their target, preventing an horrific disaster."
Prime Minister Binali Yildirim on Thursday said Turkey was facing a relentless threat: "Daesh perpetrates one event. The PKK carries out the next one and then says 'you're next' and FETO perpetrates the following one."
Meanwhile, a Turkish court on Thursday handed down life sentences to two former army officers over their involvement in the failed July 15 coup and for their involvement with the Fethullah Terrorist Organisation (FETO).
TRT World's Ali Mustafa reports.