NEW YORK (AFP) - The FBI said on Tuesday it was investigating the sighting of a small unmanned aircraft near New York's John F. Kennedy International Airport, and asked the public for help locating its operator.

Described as black in color and no more than three feet wide with four propellers, the plane came within 200 feet Monday of an Alitalia jet that was making its final approach to land at JFK, the FBI said.

"The FBI is asking anyone with information about the unmanned aircraft or the operator to contact us," said John Giacalone, the FBI special agent in charge. "Our paramount concern is the safety of aircraft passengers and crew." The Federal Aviation Administration said the sighting was reported by the pilot of the Alitalia jet.

He said the craft was six to eight kilometres south-east of the airport "at an altitude of approximately 450m" the FAA said.

It added that the pilot did not take evasive action and the Alitalia jet landed safely.

"We saw a drone, a drone aircraft," the pilot can be heard in a radio communication to the control tower, which was disseminated by the website LiveATC.net.

The control tower then warned other aircraft that were in the area of the plane's presence.

The remote-controlled model aircraft are not allowed to fly higher than 120m and must notify a control tower or airport operator if they are within five kilometres of an airport, according to the FAA.