A suspected suicide bomber wounded 32 people in an attack targeting Turkish police in Istanbul's main square today.
No organisation has claimed responsibility, officials said, though the city has been targeted in the past by Kurdish separatist militants and al-Qaeda, as well as militants from Turkey's far-left.
"It was a suicide bomb and it appears as if the bomber blew himself up. It appears to be a male body," Istanbul police chief Huseyin Capkin told reporters.
Fifteen policemen and 17 civilians were wounded in the attack in Taksim Square, but only nine, mostly police, were kept in hospital, Istanbul Governor Huseyin Avni Mutlu told reporters.
Taksim Square is a major tourist and transport hub, surrounded by restaurants, shops and hotels, at the heart of modern Istanbul.
The bomber struck near police buses parked close to a monument commemorating Mustafa Kemal Ataturk, the founder of modern Turkey, and victory in the war of independence in 1923.
The police presence in Taksim is raised around national holidays like Republic Day, which was celebrated on Friday.
A taxi driver told CNN Turk news channel he saw a 30 to 33-year-old man approach the police to ask directions, at which point the bomb detonated. Another witness said he saw two men.
According to the governor, police seized plastic explosives found with a detonator at the scene, though it was unclear whether they had been part of a second bomb, that some media reported had been found.
A bomb disposal unit was at the scene, and forensic teams pored over debris scattered over the square, which remained sealed off hours after the blast.
Prime minister Tayyip Erdogan was visiting Mardin, in the mainly Kurdish southeast, when the blast struck his hometown.
"Those who threaten Turkey's peace, security and development will not be tolerated," he said in a televised speech.
"These kinds of attacks will not stop Turkey reaching its goals of peace, brotherhood and development. We are together, we are brothers." Istanbul is the business and financial centre of Turkey, an overwhelmingly Muslim nation of 75 million people that is hoping to become a member of the European Union.
The city has been targeted before by Kurdistan Workers Party (PKK) rebels, but the separatist group extended a unilateral ceasefire last month, and on Saturday said it would announce in the coming days whether it would extend it further.
Reuters