The attack was triggered by the remote-controlled bomb, exploded as a shuttle bus carrying police officers was passing in the Beyazit district of the city on Tuesday morning, Turkey’s state-run TRT channel reported.
There was no immediate claim of responsibility. But Kurdish militants, Daesh (ISIL/ISIS) and radical leftists have all staged attacks in Turkey recently.
Ambulances and fire engines were dispatched to the scene.
Turkey has suffered a spate of bombings this year, including two suicide attacks in tourist areas of Istanbul blamed on Daesh and two car bombings in the capital, Ankara, which were claimed by a Kurdish militant group.