A distress call was sent before the Germanwings Airbus A320 flight crashed in the French Alps, with 148 people on board, the French transport minister has said.
Alain Vidalies said the call was issued at 10.47 am when the aircraft was at 5,000 feet and in an "abnormal situation".
During a visit to the crash site, the boss of Lufthansa has avoided reporters' questions about the co-pilot's known depression.
Newly-released footage shows Germanwings co-pilot Andreas Lubitz in flight around ten years ago during his time as a trainee.
Pilots with a history of depression should not be banned from flying, a leading British psychiatrist has said.