Two of the wounded were seriously injured and receiving treatment at a hospital, but none were in critical condition, Police Chief Celalettin Cerrah said. Most of the injuries were caused by flying glass, he said.
Police said they suspected the blast was caused by a percussion grenade, a type of explosive that usually makes a loud noise but causes limited damage.
The Anatolia news agency reported that the suspected bomb was left in a trash container, and that the force of the blast shattered windows nearby, sending glass flying onto the street and sidewalk.
Most of the injured were treated on site as police cordoned off the area and tried to maintain order, Anatolia said.
Television footage from the site showed shattered glass scattered along a sidewalk, and at least one policeman was seen firing a gun into the air, apparently trying to keep members of a crowd from attacking a man they thought had set off the explosion.
Kurdish militants have left bombs in Istanbul and threatened more attacks after widespread recent rioting in Turkey's Kurdish-populated southeast. Militant leftist groups also have carried out attacks in Istanbul, and frequently use percussion grenades.Reuse content