French authorities have denied reports in the prestigious French daily newspaper La Monde that the black box data recorders from crashed Air France flight AF447 have been located.

Investigators from the French Bureau d’Enquetes et d’Analyses (BEA), the French accident investigation board, said, “We can not confirm that the black boxes have been found”.

Martine del Bono, spokeswoman for the BEA, said “There are always signals detected that must be analyzed. It’s not the first time that sounds have been heard. The search is continuing and we have not yet found the recorders”.

Early Tuesday (Paris time), La Monde reported on its website that weak signals emitted by the beacons of the two recorders were detected by French ships Monday and that the French mini-submarine Nautile was diving to try and recover them.

The black boxes - a cockpit voice recorder and a flight data recorder - are considered essential to the success of the investigation into the crash of the Airbus A330-200 aircraft.

The search to recover the recorders has turned into a race against time, since the signals are emitted for only 30 days, or until the end of this month.

With less than a week remaining before the recovery beacons start to run out of power and fade away to nothing, officials admit the chances of finding the vital recording equipment and unlocking the mystery of what caused an almost new Airbus jetliner to plummet from the sky look bleak.

Despite a massive air and sea search the bodies of only 50 of the 228 passengers and crew on board the ill fated flight have been recovered.

The search for the airplane is made difficult by the mountainous terrain on the seafloor and depths of up to 4,800 meters.

Air France AF447 departed Rio de Janeiro at 7pm (BRT) and was due to arrive at Paris’ Charles de Gaulle 2 airport at 11.15am local Paris time (0915 GMT).

Air traffic controllers lost contact with flight AF447 three hours into the flight when the aircraft was some 1,500 miles (2,400km) northeast of Rio.

The flight was carrying 126 men, 82 women, 7 children and one baby.

The aircraft had reported electrical failure and strong turbulence before contact was lost and sent two dozen automatically generated systems failure reports over four minutes, leading many to believe the aircraft broke-up in mid air.