Istanbul Gov. Ali Yerlikaya confirmed the casualty in the incident on his social media handle.

"According to initial reports, in the explosion that took place on Istiklal Avenue, 4 people lost their lives and 38 people were injured. Our wounded are being treated. We wish God's mercy on those who lost their lives and a speedy recovery to the injured. Developments will be shared with the public," he wrote on Twitter as quoted by Daily Sabah.

In an earlier post, Gov. Yerlikaya wrote: "Today, at around 16.20, an explosion occurred in Taksim Istiklal Street in our BeyoÄŸlu district. Our police, health, fire and (Disaster and Emergency Management Authority) AFAD teams were sent to the scene. There are casualties and injuries. Developments will be shared with the public."

Police and other emergency service officials have rushed to the spot.

The cause of the blast is still not known.

The entire area was evacuated after the blast.

The site of the blast is a popular tourism destination in the city.