Six people were injured in a stabbing inside Penn Station on Sunday evening, sending emergency crews rushing into one of the busiest transit hubs in the country.
The violence unfolded around 7 p.m. inside the rail station beneath Madison Square Garden.
Amtrak police say six people were stabbed and taken to hospitals. Their injuries ranged from minor to serious, but all are expected to survive.
A person was taken into custody at the scene, and investigators say a knife was recovered.
Video posted to the Citizen app showed a large emergency response inside the station as crews treated victims and secured the area.
Many questions remain unanswered. Investigators have not said what led up to the stabbing, whether the victims were targeted or whether the people involved knew each other.
Because Penn Station is Amtrak property, Amtrak police are leading the investigation.
The attack happened less than 24 hours before thousands of basketball fans are expected to flood the area for Game 3 of the NBA Finals at Madison Square Garden.
President Donald Trump has also said he plans to attend the game, which is expected to bring an even larger security presence to the neighborhood.
As of Monday morning, train service was operating normally, and there were no announced changes to security around Penn Station or Madison Square Garden.
New York City Mayor Zohran Mamdani called the attack "horrific" and said his heart is with the victims, their loved ones and everyone shaken by the violence.
Investigators are expected to release additional information as the case develops.