Search and rescue craft rushed to the area in the vicinity of West 14th Street in Lower Manhattan immediately after the midair collision at noon (1600 GMT), and police divers started looking for survivors and wreckage.

Bloomberg said the plane, a Piper Saratoga, appeared to hit the back of the helicopter, which immediately broke up and fell into the river.

Police have found one piece of wreckage in murky waters and the search for bodies and debris would probably continue for a few days.

The National Transportation Safety Board said in a statement it had dispatched a 10-member team to investigate the collision.