The pilot believed to have deliberately crashed a Germanwings plane into the Alps last week had told officials at Lufthansa's flight training school that he had suffered from severe depression, the airline said.

Lufthansa's CEO had previously said the company was not aware of anything that could have driven the co-pilot to crash the Airbus A320 into the French Alps and that he was 100 percent fit to fly.

Lufthansa said Andreas Lubitz broke off his pilot training for a period of several months but then passed medical checks confirming his fitness to fly.

When he resumed training in 2009, he provided the flight school with medical documents showing that he had gone through a "previous episode of severe depression," Lufthansa said, citing emailed correspondence between Lubitz and the flight school.

Duesseldorf state prosecutors said on Monday Lubitz had been treated for suicidal tendencies before getting his pilot's licence.

They last week found torn-up sick notes showing that Lubitz was suffering from an illness that should have grounded him. Germanwings said it had not received a sick note from Lubitz for the day of the crash.

Lufthansa said it had passed the email correspondence and additional documents to the Duesseldorf prosecutors after internal investigations.

Lufthansa was already facing unlimited liability for damages in the crash, lawyers have said, and has told its insurers to set aside $300 million to deal with claims, recovery costs and the loss of the aircraft.

Tuesday's statement is likely to raise further questions over pilot screening processes.

Lawyers representing some of the families of victims of the Germanwings crash called for more psychiatric testing of pilots.

TIMESTALK DISCUSSES THE TRAGEDY

Air Malta Captain Patrick Calleja gave an insight into the Germanwings crash this evening when TimesTalk discussed the tragedy.

Follow his arguments in the three videos below.

The full programme will be repeated on timesofmalta.com tomorrow.