French President Francois Hollande gave a moving speech on Wednesday during a press conference in the picturesque Alpine village of Seyne-les-Alpes in southern France.

He was joined by German Chancellor Angela Merkel, and Spanish counterpart Mariano Rajoy a day after a Germanwings Airbus A320 went down in the mountainous region.

All 150 passengers and crew on board the flight died when the aircraft suddenly plunged from the sky as it was en route from Barcelona to Düsseldorf in western Germany. The majority of the victims were French, German and Spanish.

"Dear Angela, dear Mariano, rest assured ... we will find out everything and we will shed full light on the circumstances of this catastrophe," Hollande told Merkel and Rajoy at the press conference.

"France stands by you," he said.

Hollande pledges to discover cause of crash

Hollande told the press conference that the authorities would find out what caused the plane to plunge into the French Alps without apparent warning or reason.

The French president also confirmed that the casing from a second black box had been found, but that investigators were still searching for the box itself.

In Paris, a live press conference was held simultaneously where French air accident investigators confirmed Hollande's statement.

They also said that the aircraft's descent lasted ten minutes and that the cockpit recorder could tell them if the pilots were conscious as the flight went down.

France, Germany, Spain united in grief

Merkel said she was "moved" by the actions of the French people and residents in the Alps

The European leaders each paid tribute to the victims and remembered their friends and relatives.

They also expressed their heartfelt thanks to everyone involved in the rescue operation, which had been hampered by the rugged location of the crash site and weather conditions.

They announced that up to 800 friends and relatives could be flown to the scene and that a major support network would be in place as the process of recovering the debris and bodies of the victims could be lengthy.

Chancellor Merkel said that "everything will be ready if they do want to come to the place where this terrible tragedy happened," and that "it is a catastrophe in a very difficult geographical region."

She said that she was very moved by the response from the French people and Alpine residents "who have shown exemplary readiness to help, a lot of commitment and a big heart."

"They have our support," she continued.

She thanked France for its rapid response and cooperation over the air crash "on behalf of millions of Germans."

Merkel finished by saying, "Merci beaucoup et bon courage."

Spain's Mariano Rajoy expressed similar sentiments, saying that Madrid wanted to assist "with all the means at our disposal, to identify the victims and bring them back to their countries in the best condition possible, as this is very important."

Rajoy also thanked Paris in an equally moving gesture of solidarity.

"I would like to thank, in a special way, the French people and Hollande," he said.

The three shook hands and kissed cheeks at the end of the press conference, which in the main, thanked the people of the French Alps for their strength and support in the face of such a devastating incident.

lw/kms (AP, Reuters)