At least six people have been killed and 53 others were wounded Sunday in Istanbul after an explosion rocked a busy pedestrian street, government officials said.

Turkey's state-owned media said the cause of the blast is not known. There have been unconfirmed reports that it was a bomb explosion.

Footage from the explosion on social media show civilians fleeing the scene following the explosion.

Istanbul governor, Ali Yerlikaya, said the explosion occurred at around 4:20 p.m. local time and that fire, police, and AFAD teams have been sent to the scene.

"We wish God's mercy on those who lost their lives and a speedy recovery to the injured," Yerlikaya tweeted. "Developments will be shared with the public."

The Radio and Television Supreme Council, Turkey's media watchdog, issued an audio and visual broadcast ban surrounding the event about an hour after the explosion.

"It is essential to assist our police and health teams regarding the explosion on Istiklal Street, and to avoid posts that may cause fear and panic. All relevant teams are in the region, we will provide healthy information," Istanbul Mayor Ekrem Imamoglu tweeted.

Turkey was previously targeted with a string of bombings from 2015 to 2017 which included a deadly suicide bombing on the same street in March 2016.

Explosion