A suicide bomber set off a bomb in front of a police post near Istanbul's main square on Monday, killing two policemen and injuring 21 people.
There was no immediate claim of responsibility for the blast but police named the bomber as Ugur Bulbul, saying he was a 25 year-old Turkish national.
Bulbul approached a police post where officers who patrol the square gather and detonated the bomb.
17 of the injured were police officers.
Fragments of human bodies covered the area.
Police hurriedly covered them with newspapers held in place by stones.
The windows of several buildings were shattered.
Ambulances and firefighters rushed to the area and a police helicopter circled overhead.
An olive green armoured personnel carrier with mounted machine guns was parked in the area where the blast took place.
Turkish police routinely use armoured personnel carriers in major cities.
Istanbul's Taksim Square is a popular tourist destination.
The blast took place some 150 metres (yards) from the German Consulate.
The area in the heart of Istanbul also contains many large hotels and several other diplomatic missions.
Prime Minister Bulent Ecevit said that a female Australian tourist was among the injured.
Police were trying to defuse another bomb found in the area.
It is not the first time that a suicide bomber carried out an attack in Turkey.
Leftist militants and Kurdish rebels who fought for autonomy in overwhelming Kurdish southeastern Turkey have carried out several such attack in Istanbul and other cities in the past years.
The last suicide bombing was in January, when a member of a radical Marxist group entered a cafeteria in a police station and detonated bombs strapped to his chest, killing himself and a police officer.
Radical Islamic groups are also active in Istanbul.