A photo released March 25, 2015 by the French Interior Ministry shows debris at the crash site of an Airbus A320, near Seyne-les-Alpes.  [Photo/Agencies]

As well as Germans and Spaniards, victims included three Americans, a Moroccan and citizens of Britain, Argentina, Australia, Belgium, Colombia, Denmark, Israel, Japan, Mexico, Iran and the Netherlands, officials said. However DNA checks to identify them could take weeks, the French government said.

Lufthansa CEO Carsten Spohr described the crash as incomprehensible and said Lufthansa has never lost a plane during the cruise stage of flight.

"This represents the darkest hours in the 60 year history of our Lufthansa group. We are still in a state of shock," he said.

Hollande, Merkel and Rajoy thanked search teams and met residents in the village of Seyne-les-Alpes, where the salvaging operation has been set up.

"Dear Angela, dear Mariano, rest assured ... we will find out everything," Hollande told German Chancellor Angela Merkel and Spanish Prime Minister Mariano Rajoy, pledging to get to the bottom of what caused the crash. "France stands by you."

Merkel replied: "It feels good that in a difficult hour like this that we're standing so closely together in friendship. Dear Francois, I'd like to say to you a heartfelt 'thank you' in the name of millions of Germans who are deeply appreciative of this German-Franco friendship."