Istanbul explosion: 'Bomb attack' on busy pedestrian street leaves six dead and dozens injured, president says

At least six people have been killed and 81 injured after an explosion on a busy pedestrian street in central Istanbul, Turkey's president has said.

People ran away following the blast on Istiklal Avenue in the Taksim area, with video posted online showing flames erupting and a loud bang.

President Recep Tayyip Erdogan called the explosion a "bomb attack" and said six people were killed and 53 wounded.

Speaking before his departure to the G20 summit in Indonesia, Mr Erdogan said the explosion was a "treacherous attack" and its perpetrators would be punished.

"Efforts to defeat Turkey and the Turkish people through terrorism will fail today just as they did yesterday and as they will fail again tomorrow," Mr Erdogan said.

"Our people can rest assured that the culprits behind the attack will be punished as they deserve," he said.

He added that initial information suggested "a woman played a part" in the attack.

"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."

Istanbul's governor Ali Yerlikaya also tweeted: "We wish God's mercy on those who lost their lives and a speedy recovery to the injured."

He said the explosion happened around 4.20pm local time (1.20pm GMT).

State broadcaster TRT showed videos of ambulances and police heading to the scene.

'I was petrified'

"When I heard the explosion, I was petrified, people froze, looking at each other. Then people started running away. What else can you do," restaurant worker Mehmet Akus said.

"My relatives called me, they know I work on Istiklal. I reassured them," he added.

The cause of the blast was not immediately known.

Five prosecutors have been assigned to investigate the explosion, state-run Anadolu news agency said.

No one has claimed responsibility for the attack.

Broadcast ban imposed

Turkey's RTUK regulator imposed a broadcast ban on coverage of the blast around an hour after it occurred. It prevents broadcasters from showing videos of the moment of the blast or its aftermath.

Istiklal Avenue is a pedestrian thoroughfare popular with tourists and locals and is lined with shops and restaurants.

Turkey suffered several deadly bombings between 2015 and 2017 by Islamic State and outlawed Kurdish groups.