Fire personnel responding to reports of smoke at the 36th Street station in the Sunset Park area found multiple people shot and undetonated devices, a New York City Fire Department spokesperson said.
It is understood that preliminary information indicates a suspect was dressed in construction gear.
According to local reports, at least five people were said to have been shot
A photo from the scene showed people tending to bloodied passengers lying on the floor of the station.
New York City police said they were responding to reports of people wounded either by gunfire or an explosion.
Trains servicing that station were delayed during the morning rush hour.
The NYPD warned New Yorkers to avoid the area and to expect emergency vehicles and delay while locla schools were placed in lockdown.