It was the co-pilot's "intention to destroy the plane," the prosecutor said.

Robin said the co-pilot had never been flagged as a terrorist, and would not give details on his religious or ethnic background, AP reported.

Lufthansa, the parent company of Germanwings, said Lubitz joined the airline in September 2013 and had flown 603 hours.

"We from Lufthansa are speechless that this aircraft was deliberately crashed by the co-pilot," said Lufthansa CEO Carsten Spohr in a news briefing before reporters Thursday.