German Chancellor Angela Merkel says she will travel to the crash site of Germanwings Flight 4U 9525 tomorrow.
She said the incident - which is feared to have left 150 people dead - had plunged Germany, France and Spain into "deep mourning".
Merkel said all three countries would work together to establish the cause of the crash.
"I will travel there tomorrow to get my own impression and to speak with local officials," she told reporters.
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.