New York, 12 April (CNN)- Multiple people were shot and 13 people were hospitalized in an incident at a Brooklyn subway station during Tuesday morning rush hour, authorities said.

A preliminary investigation shows a possible smoke device was detonated at the station, according to a senior law enforcement official. The NYPD said that there were no active explosive devices at this time.

The incident began at about 8:30 a.m. when the Fire Department of New York was called to the 36th Street subway station in Brooklyn's Sunset Park neighborhood for a report of smoke.

Two sources said that five people were shot. Police said, citing a preliminary report, a male perpetrator possibly wearing a gas mask and orange construction vest fled the scene.

Police told the public to avoid the area of 36th Street and 4th Avenue in Brooklyn, where a large presence of emergency responders gathered.

New York City Mayor Eric Adams, who has Covid-19, has been briefed on the situation, his spokesperson Fabien Levy said.