By Eric Levenson, Shimon Prokupecz and Miguel Marquez, CNN

(CNN) -- A helicopter crash-landed on the roof of a midtown Manhattan building Monday, sparking a fire and killing the pilot, the FDNY said.

"The fire has been extinguished, and members continue to operate in response to fuel leaking from the helicopter," the FDNY said.

Preliminary information is that only the pilot was on board the twin-engine Agusta A109E helicopter when it crashed on the roof of 787 7th Avenue, FAA spokeswoman Kathleen Bergen said. FAA air traffic controllers did not handle the flight, and the NTSB will be in charge of the investigation, Bergen said.

New York Gov. Andrew Cuomo said the helicopter made an emergency landing on the roof, and that people in the building said they felt the building shake.

The FDNY said firefighters climbed to the top of the 51-floor building, which was evacuated.

The NYPD said to avoid the area of West 51st Street and 7th Avenue due to the ongoing investigation and to expect emergency vehicles and traffic in the area.

At the time of the incident, moderate to heavy rain was falling in the city and visibility at Central Park was down to 1.25 miles. Winds were from the east at 9 mph.

Lance Koonce said he heard something that sounded like a helicopter flying very low, and when he looked out the window he saw a sheet of flame and smoke.

"It was over pretty quickly, and even the smoke did not last long," he said.

Witness felt the building shake

Video from the scene showed dozens of emergency vehicles with lights flashing. About 100 Fire and EMS units have responded, according to FDNY. There are 25 fire department units on scene.

Nathan Hutton, who works in IT in the building, told reporters about the chaos in the building as people tried to evacuate.

"It took a half hour to get from the 29th floor down to the ground floor. There were just too many people, it was too crowded, and everybody was trying to get off on all the floors at the same time," he said.

"You could feel the building shake, and you could actually hear the alarms."

He said when alarms went off, security told people to evacuate the building via the stairs and not the elevators.

"We could feel it when it hit but no one knew what it was," he said.

Cuomo said the incident brought back memories of the September 11, 2001, terrorist attacks for New Yorkers.

"If you're a New Yorker, you have a level of PTSD from 9/11," he said. "And I remember that morning all too well. So as soon as you hear an aircraft hit a building, my mind goes where every New Yorker's mind goes."

President Donald Trump tweeted that he had been briefed on the crash.

"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," he tweeted.