Turkish President Recep Tayyip Erdogan says the blast on a busy Istanbul thoroughfare was a ‘treacherous attack’.

Six people have been killed and 81 others wounded as an explosion rocked a busy pedestrian street in central Istanbul, in an incident that President Recep Tayyip Erdogan labelled an attack that “smells like terrorism”.

On Sunday, ambulances raced to the scene on the packed Istiklal avenue, which police had quickly cordoned off. The area, in the Beyoglu district of Turkey’s largest city, had been crowded as usual at the weekend with shoppers, tourists and families.

Speaking before his departure to the Group of 20 (G20) summit in Indonesia on Sunday, Erdogan said the explosion was a “treacherous attack” and pledged that its perpetrators would be punished.

“Our people can rest assured that the culprits behind the attack will be punished as they deserve,” he said at a press conference, adding that initial information suggested “a woman played a part” in it.

“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.

Four people died at the scene and two died in the hospital, Erdogan said.

Vice President Fuat Oktay later updated the wounded toll to 81, with two in serious condition, and also said it appeared to be a “terrorist attack”.

The explosion occurred at about 4:20pm (13:20 GMT) on Sunday, according to officials.

A video posted online showed flames erupting and a loud bang, as pedestrians turned and ran away.