Istanbul - The Istanbul governor's office says the explosion at the city's historic Sultanahmet district has killed least 10 people.
A statement says 15 other people were injured in Tuesday's blast. The cause of the explosion is under investigation, but state-run TRT television says it was likely caused by a suicide bomber.
The private Dogan news agency says at least two people were hospitalised following an explosion in the historic center of Istanbul.
State-run TRT television says the blast was likely caused by a suicide bomber, but authorities have not commented on the cause.
Private NTV television said the explosion was close to a park that is home to a landmark obelisk. The state-run Anadolu Agency says several police and medics were sent to the area.