At least two people were killed and 17 others injured Wednesday after a three-story residential building collapsed into an adjacent construction site in Brooklyn, New York, according to city officials.

The collapse occurred at approximately 4.01 pm local time (2101GMT) at 1321 Flatbush Avenue, prompting a major emergency response, New York City Fire Department (FDNY) Fire Commissioner Lillian Bonsignore told reporters.

Multiple people inside the residential building and at the neighboring construction site were trapped following the collapse, Bonsignore said.

"We have 19 patients. Sadly, we have two that are deceased, four that are critical, 12 that are stable, and we also have one firefighter with minor injuries. Of those 19, seven are children," she added.

New York City Mayor Zohran Mamdani described the incident as a "devastating collapse," warning that the casualty figures could change as rescue operations continue.

"The Department of Buildings and our law enforcement partners will be leading an investigation into the cause of this building collapse," he said.

Emergency crews continued search-and-rescue operations at the scene, while officials said they had yet to determine how many people remained in the collapse zone. (AA)