Sixteen people have been injured by a bomb explosion in central Istanbul.
The explosion occurred during Istanbul's morning rush hour. Many of those wounded were police officers traveling in a bus to work.
Istanbul Police Chief Huseyin Capkin explained what investigators believe happened. They think the explosion was caused by a bomb that was remotely detonated. He said the intended target of the attack appeared to be the police vehicle carrying 21 officers.
Istanbul Governor Huseyin Avni Mutlu said it was believed plastic explosives were used and were placed on a motorcycle.
The prime suspects are the Kurdish rebel group the Kurdistan Workers Party. The group known as the PKK has been fighting the Turkish government for greater Kurdish rights since 1984.
In the past few years similar attacks on security forces have been blamed on the PKK. Security forces in the last few months have detained hundreds of people accused of supporting the Kurdish rebel group.
Turkish Prime Minister Recep Tayyip Erdogan said the attack carried the hallmarks of Kurdish militants.
"We will never bow to such attacks," Erdogan told a televised news conference. He said his government would continue the struggle against terrorism and the culprits will be captured as soon as possible.
Despite the accusations, no one has clammed responsibility for the blast. Numerous other groups, ranging from the far left to Islamic militants, have in the past been responsible for bombings in Istanbul.