'No wreckage found' in plane search

Confusion broke out after Brazilian officials said that a helicopter had found an airplane cargo pallet from the Air France flight -- only to retract the claim hours later.

France's transport minister Dominique Bussereau suggested that searchers were back to square one in the hunt for Flight 447 bound from Rio de Janeiro to Paris, which went down after leaving Brazil.

"French authorities have been saying for several days that we have to be extremely prudent," Mr Bussereau said. "Our planes and naval ships have seen nothing."

A French defence ministry official said French teams "cannot precisely confirm the zone where the plane went down".

Meanwhile, Brazil's air force was flying designated relatives of victims from Rio de Janeiro to the military's search command post in the north-eastern city of Recife to tour the operation and ask questions. Recife has a large air force base where debris and any human remains will be brought after being picked up at sea.

The pallet Brazilian officials initially said came from the plane was made of wood, and the plane was not carrying wooden pallets, Brazilian air force general Ramon Cardoso said, adding that "so far, nothing from the plane has been recovered".

He said a large oil slick spotted by search plane pilots was not from the Airbus, but that another slick found may have been from the downed passenger jet.

"The oil was not from the plane because there wasn't oil of that quantity (on the plane) to cause that slick," he said.

Bussereau said the search must continue and stressed that the priority was finding the flight recorders. The plane went down with 228 people on board in the world's worst aviation disaster since 2001.