The pilot was killed when a helicopter made a hard landing Monday on the rooftop of a high-rise building near Trump Tower.
The chopper, an Agusta A109E, took off from the 34th Street heliport on Manhattan's east side at 1.32 pm and crashed 11 minutes later, New York Police Commissioner James O'Neill said.
Flying in rain and fog, the pilot, identified as Tim McCormick, encountered problems and tried to make an emergency landing on the roof of a 54-story tall building at 787 Seventh Avenue.
Authorities quickly ruled out terrorism.
McCormick was the only person aboard the helicopter, registered to American Continental Properties, LLC.
"We were able to put water on the fire quite quickly," New York Fire Commissioner Daniel Nigro said. "Unfortunately, we did find a victim with the helicopter."
The pilot was the only fatality, Nigro said.
The building was evacuated as a precaution while firefighters put out the flames and contained the fuel leaking from the aircraft.
"We had a very strange, very troubling incident this afternoon here in Manhattan," Mayor Bill de Blasio told reporters, stressing the absence of any "indication at this time that this was an act of terror and there is no ongoing threat to New York City based on all the information that we have right now."
"This could've been a much worse incident, and thank God that no other people were injured in this absolutely shocking, stunning incident," the mayor said.
The building where the helicopter crashed is located near Trump Tower, an area that has been closed to aircraft since Donald Trump became president of the United States in January 2017.
The flight restrictions are in effect regardless of whether or not Trump or members of his family are present in Trump Tower.
Officials were still trying to determine whether the pilot obtained permission to enter the restricted airspace, De Blasio said.
Trump was told about the incident and took to Twitter to praise New York police and firefighters for their handling of the emergency.
"I have been briefed on the helicopter crash in New York City. Phenomenal job by our GREAT First Responders who are currently on the scene. THANK YOU for all you do 24/7/365! The Trump Administration stands ready should you need anything at all," the president tweeted.
The governor of New York state, Andrew Cuomo, said authorities had "no indication" the crash was anything other than an accident, while acknowledging that it was natural for residents to fear the worst in light of the attacks of Sept. 11, 2001.
"If you're a New Yorker you have a level of PTSD (post-traumatic stress disorder) from 9/11 and I remember that morning all too well. So as soon as you hear an aircraft hit a building, I think my mind goes where every New Yorker's mind goes," he said.
Federal Aviation Administration air traffic controllers "did not handle the flight," the agency said, adding that the National Transportation Safety Board would investigate the cause of the accident.
Prior to Monday, the most recent fatal helicopter crash in New York was on Oct. 4, 2011, when a chopper plunged into the East River shortly after takeoff, leaving three people dead.