Buffalo NY – A firefighter died inside a burning building in downtown Buffalo, New York, on Wednesday, where a fire and an explosion sent flames and smoke billowing into the street.

Video recorded by bystanders showed teams of firefighters outside the building being knocked over and enveloped in a cloud of ash, then flailing to regain control of spraying hoses.

The firefighter was reported missing shortly after crews arrived at the commercial building, which held a theatrical costumes shop. Rescuers initially held out hope that he would be found alive as crews tried for hours to reach the spot where he was believed trapped.

Eventually the scene turned grim and firefighters stopped to salute as an ambulance drove away from the scene.

Mayor Byron Brown confirmed the death Wednesday afternoon.

“I am deeply saddened to report that a member of the Buffalo Fire Department has lost his life while bravely fighting the four-alarm fire on Main Street in Downtown Buffalo today,” he said in a statement. “I ask everyone to keep the family and fellow firefighters in your prayers.”

The firefighter’s identity was not immediately released.

Firefighters responded to the blaze in the downtown commercial district at about 10 a.m., Buffalo Fire Commissioner William Renaldo said.

“Quickly thereafter there was a mayday call,” Renaldo said at a briefing before the firefighter’s body was found. “There was a structural collapse, an interior collapse. Firefighters had to evacuate. And unfortunately one of our firefighters was trapped and is still trapped, and we’re still trying to make our way to that firefighter as we speak.”

The cause of the fire is under investigation. Renaldo said his department was investigating a report that workers had been seen with torches near the building, which was being renovated.