At least 15 people have been injured in what appears to have been a suicide bomb attack in the centre of Istanbul, Turkish media say.
Police have cordoned off the area around Taksim Square where the blast occurred on Sunday morning.
Television pictures from Taksim Square showed body parts lying on the ground.
No group has said it carried out the attack, but a two-month-old ceasefire by Kurdish rebels was due to expire later on Sunday.
Ambulances have been taking some of the injured to hospital, while medical staff are treating others at the scene.
The blast occurred near the independence monument in Taksim Square, says the BBC’s Jonathan Head in Istanbul, near a point where anti-riot police are stationed.
Istanbul police chief Huseyin Capkin said six of the injured were civilians, while nine were policemen.
Our correspondent says suspicion is likely to fall on Kurdish separatist factions or groups linked to al-Qaeda.
The Kurdish separatist PKK party has carried out bomb attacks in Istanbul in the past, as have extreme left-wing and Islamist groups.
Taksim Square is on the European side of Istanbul and is a popular destination for tourists.