A helicopter crashed into the Hudson River in New York on Thursday, emergency services said, as local media reported multiple deaths in the incident.

Several people were pulled from the water and taken to a hospital in New Jersey, the NBC4 broadcaster reported citing law enforcement at the scene, adding that four had died.

ABC7 reported three fatalities, although emergency services had yet to confirm any toll.

Images showed the chopper's landing skids protruding from the river beside Manhattan's West Side Highway as several boats clustered around the impact site. 

Police from both New York and New Jersey, which is on the opposite side of the river from Manhattan, were at the scene along with fire department vessels.

The NBC4 channel reported that its own helicopter was unable to take off because of conditions, with the weather in New York on Thursday windy under thick cloud cover.

Witnesses told the outlet that the main rotor blade had come loose from the aircraft.

Aircraft tracking service FlightRadar24 reported that based on air traffic control data the helicopter was likely a Bell 206L-4 LongRanger IV.

The river is a busy shipping channel and the scene of a dramatic 2009 incident when a US Airways jet safely landed in the water. All 155 people on board escaped with their lives in an event dubbed "Miracle on the Hudson."

The river is as deep as 200 feet (60  meters) at points, and the images of the helicopter appeared to show floatation devices deployed on the aircraft's skids.

The average temperature of the river is 46 degrees Fahrenheit (8 degrees Celsius) at this time of year, according to the US Geological Survey.

There is a heliport close to the Hudson Yards development but it was unclear if the aircraft was heading to or from the facility.

"Due to a helicopter crash in the Hudson River, in the vicinity of the West Side Highway and Spring Street, expect emergency vehicles and traffic delays in the surrounding areas," the New York Police Department wrote in a statement.

A fire service spokesperson said that "we got the call at 3:17 pm (1917 GMT)" about a "helicopter in the water," but was unable to give other information.

New Jersey State Police did not immediately respond to an AFP request for comment.

There have been around 30 helicopter crashes in New York since 1980, Brooklyn Borough President Mark Levine told reporters, calling for tighter restrictions on helicopter traffic in the city.