Police arrest 18 militants planning suicide bombings

Guler did not say what targets the militants were planning to strike, but he said all those arrested were involved in building bombs and planning attacks on the March 9 attacks on the Masonic lodge, which killed two people including one of the attackers. Five people and another attacker was seriously injured.

Eight of those arrested were still being interrogated, while another 10 were to be formally charged later Tuesday, Guler said.

"We know they received political and military training in camps in Afghanistan and Pakistan," he said. "But we don’t know if they are al-Qaida camps, but the influence of al-Qaida in those camps is obvious."

Turkish authorities are still investigating whether al-Qaida was involved in the attack.