Two women have been killed and more than 20 other people injured after a massive explosion leveled two apartment buildings in New York City.
Mayor Bill de Blasio said a number of people are missing, although some may not have been inside the buildings when the blast occurred Wednesday.
"This is a tragedy of the worst kind because there was no indication in time to save people," said Blasio.
The mid-morning explosion occurred in the Harlem section, shortly after one resident in a nearby building reported the smell of leaking natural gas. The utility serving the neighborhood, Consolidated Edison, said it dispatched two crews to the scene, but that they arrived just after the explosion.
A utility spokesman would not speculate on whether a gas leak was the cause.
More than 200 firefighters responded to the five-alarm fire that followed the blast, with many of them perched on ladder trucks aiming high-pressured hoses at the demolished buildings. Thick, gray smoke billowed from the destruction.
Both buildings collapsed to the first floor and debris from the explosion littered sidewalks for blocks.
The site of the explosion is adjacent to railroad tracks, and mainline train services out of the city's Grand Central terminal were suspended as a result.