Battling currents of 5 miles per hour and a water temperature below 40 degrees, the rescuers pulled the passengers out of the submerged helicopter and brought them ashore, he said.
All five passengers were killed, James Long, a Fire Department spokesman, said early Monday morning. Two were declared dead at the scene and three died in local hospitals. Commissioner Nigro said the pilot was at a hospital and in “O.K.” condition.
“It was a great tragedy that we had here,” he said.
It was not immediately clear what caused the helicopter to crash. Witnesses said it caught their attention because it was traveling faster and at a lower altitude than the helicopters that normally fly along the East River between Manhattan and Queens.
The helicopter, a Eurocopter AS350 owned by Liberty Helicopters, was flying as a private charter to take photos, Police Commissioner James P. O’Neill said at the news conference. A brochure for Liberty Helicopters, which is based in New Jersey, says it is the only company licensed to fly within 1,000 feet of the Statue of Liberty on all of its tours.
Its pilots have been “flying safely” for 28 years, according to the brochure. The company could not be reached for comment on Sunday night.
People who witnessed the crash said they saw emergency responders pull one person out of the water — a man who was wrapped in a white blanket — and place him in an ambulance at about 8 p.m. About an hour later, three people were taken out of the water and placed on stretchers. Emergency responders were seen performing CPR on them as they were placed into ambulances.
Kaderia Melchon was walking in Carl Schurz Park on the Upper East Side of Manhattan when she said she spotted the helicopter descend into the water. Because it was red, she said she first thought it was a Fire Department helicopter.
After it crashed, it flipped over almost immediately, its landing skids pointing into the air, she said. A man emerged and shouted for help, she said.
Another witness, Xinran Jiang, who lives on Roosevelt Island with her husband, said that helicopters zoom over the East River all the time but that this one immediately caught their attention.
“It almost looked like it was landing,” Ms. Jiang, who watched the crash from her bedroom window, said. “It wasn’t moving fast. We were curious where it was going to land. Then the next minute, it was diving into the river.”
By 9:30 p.m., a tugboat had taken the helicopter to the East 34th Street Heliport.
Helicopters are a common sight over New York City’s waterways, ferrying tourists on sightseeing trips and carrying commuters. Crashes are rare but not unheard-of.
In 2004, a WNBC helicopter crashed onto a roof in the Flatbush neighborhood of Brooklyn while covering a shooting, but all three people on board survived. There were also no casualties when, in 2005, two helicopters — one of them carrying executives from MBNA Corporation, a major credit card company — crashed into the East River within less than a week.
In 2009, when a helicopter carrying five Italian tourists was struck by a single-engine airplane over the Hudson River, everyone on both aircraft died.
In 1997, an executive at Colgate-Palmolive was killed when a helicopter crashed into the East River moments after takeoff. And from 1985 to 1990, three aircraft owned by the same company, Island Helicopter, went down in the East River.
An earlier version of this article misstated the number of people who died in a 2011 helicopter crash into the East River. It was three, not one. (Two died from injuries in the following weeks.)