The explosion occurred near a courthouse entrance that is used by judges, prosecutors and other employees.
District Mayor Hasan Karadag told NTV television earlier that 10 people were wounded in the explosion and one of them was in serious condition. A firefight between three of the suspected attackers and police erupted after the blast, and two of the assailants were killed, he said.
Turkey's state-run news agency said police are looking for a third suspect who was on the run, described as wearing a black coat and a white beret.
Several ambulances and police were dispatched to the scene.
The incident follows a string of attacks, carried out by the Islamic State group or by Kurdish militants, which have left Turkey on edge.
Thirty-nine people were killed in a nightclub attack in Istanbul during New Year's celebrations. The IS group claimed that attack. On Wednesday, police had detained some 20 people in Izmir believed to have links to the nightclub attacker who is still at large.
State-run Anadolu Agency said preliminary reports said two police officers were among the wounded who were taken to nearby hospitals.
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