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.

It sparked a massive search-and-rescue operation, with more than 250 first responders at the scene in Brooklyn, trying to find survivors who may have been trapped under the rubble of the three-storey building.

Hours later, aerial video showed firefighters pulling a survivor, covered in dust, out of the debris on a stretcher. She was later said to have been a pregnant woman. 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 same, and wrote that the noise of sirens had not stopped in the area.

“I’ve never seen anything like this,” said another witness, named only as Dashik, who spoke to local television station PIX 11.

Officials are yet to identify those who died or were injured.