ISTANBUL — An explosion on one of Istanbul’s most popular pedestrian thoroughfares killed several people and injured dozens more on Sunday.

The blast on Istiklal Avenue was not immediately clear, but authorities said at least six people were killed, with at least 50 more being injured in the explosion. Five prosecutors were assigned to investigate the incident, according to the state-run Anadolu news agency.

A video posted online showed flames erupting and a loud bang, as pedestrians turned and ran away. Other footage showed ambulances, fire trucks and police at the scene. Social media users said shops were shuttered and the avenue closed down.

WGN Terrorism Analyst Tom Mockaitis said the area of the attach could be considered a prime target.

“The shops are tightly packed and it’s usually very crowded with people shopping, sightseeing and just going about their business,” Mockaitis said. “But that’s the nature of terrorism today. It’s no longer selective, it hasn’t been for a long time. It seeks a large body count for the greatest dramatic effect.”

Turkey’s media watchdog imposed a temporary ban on reporting on the explosion — a move that prevents broadcasters from showing videos of the moment of the blast or its aftermath. The Supreme Council of Radio and Television has imposed similar bans in the past, following attacks and accidents.

Istanbul Gov. Ali Yerlikaya tweeted the death toll and said those hurt were being treated.

Turkey was hit by a string of deadly bombings between 2015 and 2017 by the Islamic State group and outlawed Kurdish groups.