One person was killed and more than a dozen people were hurt when a gas explosion sparked a massive, four-alarm blaze on the top floors of a high-rise apartment building in the Bronx early Saturday morning.

Flames shot out of the 16th floor of the NYCHA building at 3485 Bivona Street shortly after midnight as firefighters worked to evacuate over 150 units in the building, leaving about 100 people homeless, officials told reporters.

A civilian, who has not been publicly identified, was pronounced dead and 14 others were wounded, including one in critical condition, FDNY Chief Kathleen Knuth said.

“We thought the building was gonna collapse,” a woman who was on the building’s 17th floor told Pix11.

Mayor Mamdani went to the scene of the blaze after it was doused by firefighters.

“There are New Yorkers inside that building who have lost all of the possessions that they hold so dear,” the new mayor said. “They’ve lost pets. There’s one resident that lost their life and, ..there is nothing that you can truly say to someone who has gone through that kind of a grief.”  

All injured victims were taken to area hospitals.

Flames and thick smoke were captured spewing out of multiple windows on the top floors of the building, according to video captured by The Post.

Another haunting image captured a resident hanging out of a window on the top floor waving a bed sheet.

Over 230 first responders from 75 units responded to the multi-alarm blaze as temperatures dropped to the low teens and below around New York City.

“It was a very, very difficult night, on a very cold night, which caused even more difficulty. The men and women of the fire department and all the first responders of our department did a terrific job putting these fires out, couldn’t have thanked them more,” FDNY Commissioner Lillian Bonsignore told reporters.

Bonsignore said there was an investigation into the smell of gas in the building 15 minutes before the explosion occurred.

“It’s a terrible tragedy, we are sending our thoughts to everyone involved,” Leila Bozorg, deputy mayor for housing and planning, said.

Residents said they were woken up by an explosion and the lights flicked on and off. And the door of the apartment where the explosion happened blew off.

“I thought that lightning hit the building or something, like a boom, like a bomb,” said a 45-year-old who identified herself as Michelle. “But when I got up and looked through the window … and there was fireballs dropping, so I was like, let’s go. We ran out, got dressed, and ran out.”

New York City Emergency Management Commissioner Zach Iscol warned of the importance of fire safety, especially with an impending catastrophic blizzard from Winter Storm Fern.

“If this happened tomorrow during the snowstorm it would’ve been a much, much different event,” Iscol said.

The cause of the gas explosion was still under investigation, according to officials.

Additional reporting by Sofia Poznansky