Brazil's defence ministry states that a merchant ship has found no trace of the missing Air France Airbus A330 in the region where a Brazilian flight reported a possible debris sighting.
The Brazilian air command says that the vessel conducted a search pattern after a TAM crew reported "bright points" in the vicinity of Dakar airspace while operating the reverse route to the Air France flight.
But it states that the vessel has not turned up "any trace" of the missing aircraft.
The search and rescue effort has intensified, with a US Lockheed P-3 maritime aircraft potentially becoming available to join three C-130s, five other aircraft and two helicopters.
Among the search fleet is an Embraer R-99 remote sensing aircraft which is conducting scans across locator frequencies and, says the Brazilian air command, will employ forward-looking infra-red equipment if conditions are suitable.