Citing Turkish authorities, media reports say at least six people have been killed and 81 wounded in an explosion in a busy area of central Istanbul.
The BBC says the blast happened at about 16:20 local time on Sunday on a shopping street in the Taksim Square area.
Turkiye’s Anadolu Agency says Health Minister Fahrettin Koca updated on the conditions of the injured, saying 39 of the i0njured were discharged. Of the hospitalized patients, five are in intensive care, while the condition of two is serious, he added.
A suspect has now 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, according to the BBC.
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 person suspected of having left the bomb had been arrested by police, and accused the Kurdistan Workers' Party (PKK) of responsibility.
The PKK is a militant group which calls for an independent Kurdish state within Turkiye. The EU and the US regard it as a terrorist organization.
No one has so far claimed responsibility for the blast.
Istiklal Street is one of the city's main arteries, which is usually packed with shoppers – was previously targeted by a suicide bomber in 2016.
