It was not immediately known how many people were aboard the aircraft.
"A helicopter earlier this evening descended into the East River near East 90 St.", said the New York Police Department (NYPD) on Twitter. At least one person was rescued from the water, he said.
Witnesses reported the helicopter hitting the river sidewards and then inverting.
Helicopter Crashes in East River Off Manhattan, Officials Report
They Mayor's spokesman Eric Phillips said the Mayor had been briefed by the police and fire commissioners. Three other passengers remain in critical condition.
A helicopter on a sightseeing tour of Manhattan crashed into the Hudson River in July 2007, shaking up the eight people aboard but injuring no one.
The helicopter became nearly completely submerged in water. At the time, the temperature was below 40 degrees Farenheit (4 degrees Celsius).
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Witnesses say the Eurocopter AS350, a model tourism companies tend to use, filled with water quickly after it went down.
The helicopter reportedly crashed near 89th Street in Manhattan around 7 p.m. Sunday. In the video the helicopter appears to hit the water and then tip over.
The Federal Aviation Administration and the National Transportation Safety Board are investigating the cause of the crash.
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Seacrest, who was accused of sexual misconduct by his former stylist, has denied the accusation against him. Katy claimed that, in the past, some TV singing competitions have looked to make fun of certain constants.
This is a developing story and will be updated.
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