At least 16 people were injured in the incident in Brooklyn on Tuesday morning.
A suspect has been arrested after a gunman filled a subway train with smoke and shot multiple people on Tuesday morning in New York City.
At least 10 people were shot and at least 16 in all were injured in the attack as a train pulled into the 36th Street station stop in Brooklyn's Sunset Park neighbourhood.
Five people were in critical condition, New York Fire Department Acting Commissioner Laura Kavanagh said, but New York's Police Commissioner Keechant Sewell said there were no life-threatening injuries.
Sewell added that the attack was not initially being investigated as terrorism, but that she was “not ruling out anything.”
She assured the public that "there are currently no known explosive devices on our subway trains."
On Wednesday, US authorities confirmed that a person of interest had been taken into custody.
Sewell said that while the train was waiting to enter the station, a gunman donned a gas mask and took a canister out of his bag and opened it, filling the train with smoke before opening fire. She said the man was wearing a "green construction type vest and a hooded sweatshirt. The colour is grey."
A train rider's video shows smoke and people pouring out of a subway car. Wails erupt as passengers run for an exit as a few others limp off the train.
Trains servicing that station were delayed during the morning rush hour.
President Joe Biden and Attorney General Merrick Garland were briefed on the incident, as was Gov. Kathy Hochul. New York City Mayor Eric Adams, who is isolating following a positive COVID-19 test on Sunday, was briefed at the mayor’s residence.
"We've made all the resources available," said NYC deputy mayor Lorraine Grillo.
New York City has faced a spate of shootings and high-profile incidents in recent months, including on the city’s subways. One of the most shocking was in January when a woman was pushed to her death in front of a train by a stranger.