RIO DE JANEIRO — An American colonel says two ships searching for the black boxes of Air France Flight 447 are ending their hunt.

A French nuclear submarine is continuing to look.

U.S. Air Force Col. Willie Berges is the Brazil-based commander of American military forces supporting the effort.

He says one ship towing a U.S. Navy listening device stopped searching Friday, while the other ship will end its search within hours.

Berges says the ships had “no success.”

Flight 447 crashed into the Atlantic Ocean off Brazil’s northeastern coast June 1, killing all 228 people on board including one Canadian.

Investigators say without the black boxes, it may be impossible to know for certain what caused the crash.