The pilot of Eurocopter AS350, who managed to go down the New York's East River during the clash, remained to be the sole survivor in the incident, authorities say.
According to media reports, a preliminary investigation revealed an audio recording of the pilot to LaGuardia Airport informing about an engine failure in the helicopter.
Earlier it had been reported that the Liberty Helicopters chopper was chartered for a private photo shoot.
According to police, the chopper is in the water around 23rd Street, New York and it has put in a request for a barge with a crane to pull it out
One of the eyewitnesses to the incident informed an emergency CPR was performed on one of the victims.
"Emergency responders pull one person out of the water, wrapped him in a white blanket and placed 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" CNN quotes the eyewitness as saying.
The chopper was being used to provide a sightseeing view of the Manhattan skyline to the visitors when the incident took place. (ANI)