At least two people have died, and more than 17 others are injured after a building in New York City collapsed into an open construction site, officials have said.
The collapse sparked a massive search-and-rescue operation, with more than 250 first responders going to the scene of the fallen three-storey building in Brooklyn.
Aerial footage has shown firefighters pulling a survivor, covered in dust, out of the debris on a stretcher. She was later said to have been a pregnant woman.
US media reports suggest the death toll is rising and officials say they do not know how many others are missing.
An investigation is under way into what caused Wednesday afternoon's sudden collapse.
Witnesses described a terrifying sound as the building came down at about 16:00 local time (21:00 GMT).
"I live literally right behind the building," one woman, Emmanuella Carilus, told the New York Times. "It sounded like a big boom, and you just heard a bunch of screaming."
The newspaper published images showing a crowd of fire trucks and police vehicles at the scene, and wrote that the noise of sirens had not stopped in the area.
Rescuers have used search dogs, drones, axes and chainsaws to carry out their work. They say they expect the effort to last several days.
The Brooklyn building was built in 1930, city records show, according to CBS, the BBC's US partner.
