The blast happened at about 16:20 local time (13:20 GMT) on Sunday in a shopping street in the Taksim Square area. Turkey has blamed Kurdish rebels.

A suspect - a Syrian woman - has been arrested, the interior minister said.

Vice-President Fuat Oktay earlier said the blast was thought to be a terrorist attack carried out by a woman.

President Recep Tayyip Erdogan said the perpetrators would be punished.

Speaking at a news conference in Istanbul, he condemned what he called the "vile attack" and said "the smell of terror" was in the air.

Justice Minister Bekir Bozdag told Turkish media a woman had sat on a bench in the area for more than 40 minutes, leaving just minutes before the blast took place.

On Monday morning, Interior Minister Suleyman Soylu said a Syrian national - Ahlam Albashir - suspected of having left the bomb had been arrested by police. She was among 47 people detained by police. He accused the Kurdistan Workers' Party (PKK) of responsibility.

The PKK denied any role in the bombing, saying "we will not directly target civilians". The militant group has been battling for decades to achieve Kurdish self-rule in south-east Turkey. Turkey, the EU and US regard it as a terrorist organisation.