No objects have been discovered by three cargo ships arriving at the area in the Atlantic off Brazil's coast where an Air France plane crashed, the Brazilian Navy said on Tuesday.

The three cargo ships from France and the Netherlands have been rerouting to the area after debris from the crashed plane was spotted.

Any recovery in the sea will be extremely difficult not only because of the depth, but also because of powerful currents and storms in the area, a spokesman for the navy told a press conference.

Wreckage from the plane was found at the open ocean in mid-Atlantic, about 640 km northeast of Brazil's Fernando de Noronha archipelago.

The first of the Brazilian navy vessels will reach the wreckage of the Air France plane on Wednesday, the spokesman said, adding that a supply ship will also leave for the crash site from the capital of Rio De Janeiro later on Tuesday.

Brazilian Defense Minister Nelson Jobim has said there was "no doubt" that a 5-km strip of debris in the high seas was from the plane that went missing in stormy weather on Monday.

The Air France Flight 447 left Rio on Sunday evening for Paris. The plane's last contact with the Brazilian air control took place some two to three hours after the take-off, when it had just passed over the Fernando de Noronha archipelago.

The 228 people aboard the plane came from 32 countries, including nine Chinese nationals.

(Xinhua News Agency June 3, 2009)