PARIS -- France's transport minister is asking investigators to keep searching for flight recorders of an Air France jetliner that crashed off Brazil last year, killing 228 people.

Dominique Bussereau's office says this "final search phase" is "an extra chance" to find the black boxes, which could help explain the causes of the disappearance of Flight 447 on June 1.

An office statement Friday said Bussereau had asked French investigation agency BEA to continue its search with Air France and planemaker Airbus.

Separately, BEA said Friday the two vessels involved in the $13.3 million third phase of search have covered 2240 square miles of ocean since it began April 2. It said the vessels would return to port for a technical stopover in the next few days.