Lufthansa says Germanwings co-pilot had 'severe depression'

Passengers watch candles and flowers for the victims of the Germanwings plane crash at the airport in Dusseldorf , Germany.

The co-pilot suspected of deliberately crashing a Germanwings plane told his bosses he had suffered from severe depression, Lufthansa has revealed, as the airlines' chief executives announced plans to visit the crash site on Wednesday.

Lufthansa, which owns Germanwings, said 27-year-old Andreas Lubitz had told the airline in 2009 about his illness after interrupting his flight training.