President Recep Tayyip Erdogan said Turkey would continue its fight against terrorism "to the end" after a bomb attack in central Istanbul left 11 people dead and 36 others wounded.
Istanbul's Governor Vasip Sahin said on June 7 that seven police officers were among the dead.
Sahin said the explosion was caused by a bomb placed inside a car and was detonated as a police bus was passing by.
The attack took place near an Istanbul University building and the city's historic quarter during the morning rush hour.
Gunshots were reportedly heard in the area after the blast.
There was no immediate claim of responsibility.
The militants of the Kurdistan Workers Party have been targeting police and military targets since July 2015, when a peace process collapsed.
The Islamic State extremist group has also been blamed for a number of bombings in Turkey.