The co-pilot of Germanwings Flight 9525 was alone at the helm of the aircraft and "intentionally" sent the plane into the doomed descent, according to a French prosecutor.

Germanwings says 150 people were aboard the plane that crashed in the French Alps on Tuesday, but it has not yet given a final toll of the victims' nationalities.

World leaders, fellow airlines and social media users have shared their sympathies for the loss of Germanwings Flight 4U9525 and the 150 people on board, when the plane crashed in the French Alps on Tuesday.