"The person who planted the bomb was detained by the Istanbul Police Department. Before that, about 21 more people had been detained," Soylu was quoted as saying by TRT World.

Turkish Health Minister Fahrettin Koca told TRT World 39 out of 81 people who were wounded during the suspected terror attack were discharged from the hospital.

“Five of the 42 wounded are in the intensive care unit, two of them in critical condition,” Koca said.

The blast occurred at around 4:20 pm local time.

Security personnel and emergency service providers rushed to the spot after the blast.

Several footage of the venue and the moment of the blast are currently circulating on the social media.

Based on initial information from Istanbul Governor Ali Yerlikaya, President Recep Tayyip Erdogan said the explosion could be an act of terrorism, reports TRT World.

"It would be wrong to say this is undoubtedly a terrorist attack, but the initial developments and initial intelligence from my governor is that it smells like terrorism," Erdogan said.

A video footage of an eye witness who was present near the blast site on Sunday has now gone viral on the social media.

Journalist Ali Mustafa shared his video and tweeted: "Explosion on Istanbul’s Istiklal street - police saying it looks like a targeted attack #Turkiye."