At least two people have died after helicopter went down in the East River of New York City on Sunday.
Three passengers are in a critical condition in hospital after being pulled out of the water by rescue divers, said city police.
The New York City fire department said the pilot managed to free himself.
Authorities confirmed it was carrying six people involved in a photo shoot, before it hit the water near Roosevelt Island at 19:00 local time (23:00 GMT).
The helicopter was owned by a tourism group, but police commissioner James O’Neill told reporters it had been privately leased by the group of photographers.
Video posted on social media showed a red helicopter appearing to make a semi-controlled descent before landing with some force in the water. It then began to tip over, its rotors still spinning and slicing into the water.
At a press conference, New York Fire Commissioner Daniel Nigro called it a “great tragedy”.
“We are told the five people were all tied tightly in harnesses that had to be cut and removed,” he said.
“It took a while for the divers to get these people out. They worked very quickly, as fast as they could. That’s 50ft[15m] of water there,” he said, adding that they also had to work against currents and water temperatures of below 4C.
Journalists at the scene reported seeing CPR being performed on the rescued passengers as they were rushed to ambulances.
The Federal Aviation Authority said it was investigating the incident.
The National Transportation Safety Board would determine the cause, it added.