Brazilian officials said late on Thursday they have so far only recovered sea "trash" from a zone in the Atlantic where an Air France jet came down, and not aircraft debris as originally thought.
"Up to now, no material from the plane has been recovered," Brigadier Ramon Cardoso, director of Brazilian air traffic control, told reporters in the northeastern city of Recife.
He said items pulled from the ocean on Thursday and originally thought to come from downed Air France flight AF 477 actually came from another source, likely a ship.
He also said a big oil slick originally thought to come from the plane probably also came from a ship, though fuel slicks detected were likely from the jet because the fuel was of a type not used by seagoing vessels.
Earlier on Thursday, Cardoso had told reporters that navy ships 1,000 kilometers (600 miles) off Brazil's shore had pulled aboard debris from the Air France plane that vanished on Monday, including a pallet from its cargo hold and two buoys.
But after inspection it was determined the pallet could not have come from the plane.
"We confirm that the pallet found is not part of the debris of the plane. It's a pallet that was in the area, but considered more to be trash," he said.
He added that the Brazilian navy crews were pulling any item out of the water and inspecting it. Anything not belonging to the Air France plane was being put aside.