French military ships searching for the black boxes of Air France Flight 447 have detected sounds in the depths of the Atlantic Ocean, but say they do not think these are coming from the plane's flight recorders.

French military spokesman, Commander Christophe Prazuck, and French investigators have denied a report by the French newspaper "Le Monde" that French ships had picked up a signal from one of the black boxes.

The two flight recorders will only continue to emit signals for another week or so.

French air accident investigation agency BEA says work is continuing and any findings will be released to the public.