French air accident investigators said on Wednesday that they will continue to locate the black boxes of the vanished Air France flight.

The black boxes could still send signals for a few days one month after the June 1 crash and therefore the efforts to locate them would continue, said a spokesman for the BEA, the French air accident authority.

According to a Wednesday report by France's Le Figaro, the search for the black boxes, which could contain vital clues to explain the crash, would continue until July 10. The report was not confirmed by the French authorities.

On Tuesday, the website of Le Monde daily reported that signals of the black boxes had been picked up and a mini submarine had been launched to try to find them. But the BEA denied the report, saying searchers had not heard any signals they could be sure came from the black boxes.

"In the context of the sea searches that are under way, work is undertaken on a regular basis that is aimed at eliminating any doubts related to any sounds that may be heard, and any findings will be made public," it said in a statement.

Air France Flight 447, an Airbus A330, went down into the Atlantic Ocean on June 1 after leaving Rio de Janeiro for Paris, killing all 228 people on board.

(Xinhua News Agency June 25, 2009)