Explosion in NYC's Chinatown

An explosion and fire in a building in New York City's Chinatown injured 12 people, including four firefighters, the Associated Press reported Thursday afternoon.

The 12:45 p.m. ET blast caused the partial collapse of the first floor, said Assistant Chief Robert Boyce. The cause was not immediately known.

The New York Daily News cited an apparent natural gas explosion. NBC News, citing an unidentified law enforcement official, said the blast may have been caused by a severed gas line in the basement. WABC-TV reported that the rear of the building may have been under construction.

The five-story building includes commercial spaces with apartments above. The New York Post reported the explosion occurred in the back of a beauty salon.