A helicopter has crashed into New York City’s East River and flipped upside down in the water, killing five of the six people aboard, officials said.

Video taken by a bystander and posted on Twitter on Sunday shows the red helicopter land hard in the water and then capsize, its rotors slapping at the water.

The helicopter, a private charter hired for a photo shoot, went down near Gracie Mansion, the mayoral residence. One person, the pilot, freed himself and was rescued by a tugboat, officials said.

The passengers were recovered by police and fire department divers, who had to remove them from tight harnesses while they were upside down, Fire Commissioner Daniel Nigro said.

“It took a while for the drivers to get these people out. They worked very quickly as fast as they could,” Nigro said. “It was a great tragedy that we had here.”

Witnesses on a waterfront esplanade near where the aircraft went down said the helicopter was flying noisily, then suddenly dropped into the water and quickly submerged. But the pilot appeared on the surface, holding onto a flotation device as a tugboat and then police boats approached.

“It’s cold water. It was sinking really fast,” Mary Lee, 66, told the New York Post. “By the time we got out here, we couldn’t see it. It was underwater.”

The Mayor was just briefed by the police and fire commissioners. At least one survivor, at least two fatalities. Divers are still in the water.

— Eric Phillips (@EricFPhillips) March 12, 2018

Celia Skyvaril, 23, told the Daily News that she could see a person on what looked like a yellow raft or float screaming and yelling for help.

News footage showed one victim being loaded into an ambulance while emergency workers gave him chest compressions.

https://twitter.com/TheAnonJournal/status/972988098488479746

A bystander, Susan Larkin, told The Associated Press that she went down to see rescue boats in the river and a police helicopter circling overhead, hovering low over the water.

“You could clearly see they were searching,” she said.

A Federal Aviation Administration spokeswoman said the Eurocopter AS350 went down just after 7pm. The aircraft was owned by Liberty Helicopters, a company that offers both private charters and sightseeing tours popular with tourists. A phone message left with the company was not immediately returned.

The skies over New York constantly buzz with helicopters carrying tourists, businesspeople, traffic reporters, medical teams and others. Crashes are not unheard of.

The cause of the crash is unknown. The FAA and the National Transportation Safety Board are investigating.

Officials did not immediately release the names of the pilot or passengers or say how the passengers died.

The helicopter was recovered in the rescue operation and towed to a pier.

Video footage shows survivor emerging from the helicopter crash in New York City's East River, officials tell CBS New York. https://t.co/363xIKBsYe pic.twitter.com/aV4r67gBaP

— CBS News (@CBSNews) March 12, 2018

-AP