New York, Aug 9 (DPA) A sightseeing helicopter with five Italian tourists on board collided with a light aircraft over New York's Hudson River Saturday, sending wreckage from both plunging into the waters.

All nine people on board the two aircraft were assumed dead, Mayor Michael Bloomberg said in broadcast remarks.

'It appears that this was not survivable,' Bloomberg said. 'This has changed from a rescue to a recovery mission.'

Two bodies had been recovered, including one that had floated free, and several bodies were in the submerged wreckage of one of the craft that had been spotted.

Bloomberg said that because of the disfigurement through the crash, it was not clear if it was the helicopter or the 1976 single-engine Piper.

'There is some evidence from eyewitnesses that one of the wings of the airplane was ... possibly severed by the rotors of the helicopter,' Bloomberg said.

Divers were searching in the murky 10 metre-depths of the swift-flowing Hudson River for other bodies and the second wreckage, Bloomberg said.

The mayor said special community affairs officials had been sent to help the families of the Italian tourists.