PARIS (AP) — French investigators said Tuesday they are extending the undersea hunt for wreckage from the Air France jet that crashed last year in the mid-Atlantic through late May, but with fewer resources.

The French accident investigation agency BEA says it believes "it is in fact still possible to localize the airplane wreckage" in or near the 770-square-mile (2,000-square kilometer) target area that was searched unsuccessfully last month.

But the BEA said only one of the two ships that have been hunting for the black box flight recorders will continue the search. The other is carrying U.S. Navy-owned equipment needed for a military operation.

The Airbus jet crashed en route from Brazil to France last June, killing all 228 aboard.

The ship that will continue the search will see its resources diminished, with only two of the previous three sonar-equipped robot submarines still deployed. The owner of the third sub, IFM-Geomar of Germany, is deploying it elsewhere for scientific research, the BEA said.

Air France and Airbus, the maker of the aircraft, will each pay euro1.5 million to finance the search's continuation until "around May 25," the BEA said.

The search focuses on a mountainous area of seabed, perhaps as much as 13,100 feet (4,000 meters) below the surface in the mid-Atlantic. The zone being searched now is only one-tenth the size of the area combed in two attempts last year.

The smaller search area was the result of an effort by scientists, including from the U.S.-based Woods Hole Oceanographic Institution in Massachusetts, to reconstruct the trajectory of the Airbus 330's debris and the time the wreckage was found, giving investigators a better idea of where to look.

Officials say locating the flight data and voice recorders is crucial, since the 1,000 pieces of wreckage already recovered have provided no concrete information as to what caused the crash.

The devices contain recordings of cockpit conversations and various data readings from the aircraft.

Without that information, investigators will probably never know why the jet flew straight into huge thunderstorms that other trans-Atlantic flights on similar routes took pains to avoid that day. Based on information gathered so far, investigators believe the plane was intact when it crashed into the ocean.