NEW YORK (Reuters) – At least 37 people have suffered non-life-threatening injuries in a New York City commuter train derailment on Wednesday during peak morning commuting hours, city officials said.

Dozens of emergency crews swarmed Atlantic Terminal in the borough of Brooklyn after the Long Island Railroad train went off the tracks at about 8:30 a.m. local time inside the busy transportation hub, the New York City Fire Department said.

The nature of the injuries was not immediately known, and the incident was under investigation, police Detective Ahmed Nasser said.

Police and firefighters, some holding stretchers, could be seen entering the terminal as emergency vehicles blocked traffic.

Commuters, meanwhile, described a frightening and chaotic scene on social media.

“People flying everywhere,” Serena Janae, who said she was a passenger on the derailed train, wrote on Facebook.

The U.S. Federal Railroad Administration said it was sending investigators to the scene.

Atlantic Terminal, which also connects commuters to nine city subway lines, is one of New York’s busiest stations.

(Additional reporting by Gina Cherelus, David Shepardson and Jonathan Oatis; Editing by Jeffrey Benkoe and Lisa Von Ahn)

IMAGE: Emergency vehicles gather at the Atlantic Avenue Terminal after a commuter train derailed during the Wednesday morning commute, in New York, U.S., January 4, 2017. REUTERS/Jonathan Oatis