Bronx high-rise partially collapses after explosion. Video shows entire side of 20-story building gone.

An explosion rocked a Bronx high-rise Wednesday morning, causing the entire side of the 20-story building to collapse. 

The FDNY said it responded to a report of a possible gas explosion, and that it appears the building’s incinerator shaft may have collapsed. At this point, no injuries have been reported. 

Videos show a gaping hole in the side of the building and extensive damage all along Alexander Avenue in the Mott Haven section of the borough. 

FDNY officials are expected to provide an update at 11 a.m. You can watch live on CBS News New York, in the video player above.

The explosion was reported around 8:10 a.m. at a residential high-rise in the Mitchel Houses, located at 205 Alexander Ave. near East 137th Street. 

One witness said she saw the smoke after dropping her kids off at school and called 911. 

“The whole building just — you heard a loud boom, and the thing just exploded, and it fell down just like that,” she said. 

According to the most recent NYCHA data, the housing complex has approximately 3,500 residents in 1,730 units across 10 residential buildings. It encompasses two city blocks and was completed in 1966. 

The blast sent bricks, air conditioning units and other debris raining down onto nearby buildings and the sidewalk and street below. Water also appeared to be bubbling up from the ground, possibly from a damaged pipe.

Firefighters could be seen digging through the rubble and using drones and dogs to make sure no one was trapped underneath.   

At this point, it’s unclear if the building has been evacuated, and there’s been no word on its structural stability. Residents told CBS News New York that at least two of the elevators were not working. 

Con Edison and other agencies are responding to the scene. Several nearby streets are closed, and drivers are facing heavy delays around the area.

Check back soon for updates on this developing story. 

Natalie Duddridge

contributed to this report.