A helicopter carrying five people has crashed into New York City's East River, killing one woman. The other people on board, including the pilot, were rescued. Two of the survivors were reported to be in critical condition.

Authorities say the Bell 206 helicopter went into the river off 34th Street in Manhattan shortly after takeoff Tuesday and sank. The cause of the accident was not clear, but news reports cite witnesses as saying the chopper appeared to have mechanical problems. Rescuers were on the scene within minutes of the crash.

New York Mayor Michael Bloomberg told reporters the four survivors managed to get out of the helicopter on their own, but that the woman who died was trapped inside. He also said the National Transportation Safety Board will conduct interviews as part of its investigation.

The mayor said the aircraft was a private helicopter from New Jersey and the pilot knew the passengers. At the time of mayor's news conference, the helicopter remained submerged in the river.