Turkish officials say a police bus was targeted in the central Istanbul district of Vezneciler with some wounded in the blast, The Sunday Express reports. A number of gunshots were reportedly heard after the explosion and police have evacuated shops, cafes and homes near the scene.
A parked car packed with explosives was detonated by remote control as the police bus passed by. The area is a major draw for tourists from around the world who flock to the historic city to marvel at the sights.
Police say no-one has yet claimed responsibility for the attack although Kurdish militants, Islamic State and radical leftists have all staged attacks in Turkey recently.Armed police, fire crews, medics and anti-terror specialists are at the scene.