French Police and Gendarmerie Alpine rescue units gather on a field as they prepare to reach the crash site of an Airbus A320, near Seyne-les-Alpes, in the French Alps, March 24, 2015. [Photo/Agencies]

An Airbus operated by Lufthansa's Germanwings budget airline crashed in a remote area of the French Alps on Tuesday, killing all 150 people on board including 16 schoolchildren.

Germanwings confirmed its flight 4U 9525 from Barcelona to Duesseldorf went down with 144 passengers and six crew on board.

One of the plane's black box recorders has been found and will be examined immediately, France's interior minister said. In Washington, the White House said the crash did not appear to have been caused by a terrorist attack. The airline believed there were 67 Germans on the flight. Spain's deputy prime minister said 45 passengers had Spanish names. One Belgian was aboard.

Also among the victims were 16 children and two teachers from the Joseph-Koenig-Gymnasium high school in the town of Haltern am See in northwest Germany, a spokeswoman said.

Investigators described a scene of devastation where the airliner crashed. Aerial photographs showed smoldering wreckage and a piece of the fuselage with six windows.

"We saw an aircraft that had literally been ripped apart, the bodies are in a state of destruction, there is not one intact piece of wing or fuselage," Bruce Robin, prosecutor for the city of Marseille, told Reuters in Seyne-les-Alpes after flying over the crash zone in a helicopter.

French police at the crash site said no one survived and it would take days to recover the bodies due to difficult terrain, snow and incoming storms.

Police said search teams would stay overnight at altitude.

"We are still searching. It's unlikely any bodies will be airlifted until Wednesday," regional police chief David Galtier told Reuters.

In Paris, Prime Minister Manuel Valls told parliament: "A helicopter managed to land (by the crash site) and has confirmed that unfortunately there were no survivors."

It was the first crash of a large passenger jet on French soil since the Concorde disaster just outside Paris nearly 15 years ago. The A320 is a workhorse of worldwide aviation fleets. They are the world's most used passenger jets and have a good though not unblemished safety record.

SHARP DESCENT

Germanwings said the plane started descending one minute after reaching its cruising height and continued losing altitude for eight minutes.

"The aircraft's contact with French radar, French air traffic controllers, ended at 10.53 am at an altitude of about 6,000 feet. The plane then crashed," Germanwings' Managing Director Thomas Winkelmann told a news conference.

Winkelmann also said that routine maintenance of the aircraft was performed by Lufthansa on Monday.

Experts said that while the Airbus had descended rapidly, its rate of descent did not suggest it had simply fallen out of the sky.

France's DGAC aviation authority said air traffic controllers initiated distress procedures after they lost contact with the Airbus, which did not issue a distress call.

"The aircraft did not itself make a distress call but it was the combination of the loss of radio contact and the aircraft's descent which led the controller to implement the distress phase," a DGAC spokesman said.

The aircraft came down in an alpine region known for skiing, hiking and rafting, but which is hard for rescue services to reach.

The search and recovery effort based itself in a gymnasium in the village of Seyne-les-Alpes, which has a small private aerodrome nearby.

Transport Minister Alain Vidalies told local media: "This is a zone covered in snow, inaccessible to vehicles but which helicopters will be able to fly over."

But as helicopters and emergency vehicles assembled, the weather was reported to be closing in.

STORMS, SNOW, CLOUD

“There will be a lot of cloud cover this afternoon, with local storms, snow above 1,800 meters and relatively low clouds. That will not help the helicopters in their work,” an official from the local weather center told Reuters.

Lufthansa Chief Executive Carsten Spohr, who planned to go to the crash site, spoke of a "dark day for Lufthansa".

"My deepest sympathy goes to the families and friends of our passengers and crew," Lufthansa said on Twitter, citing Spohr.

The airliner crashed about 100 km (65 miles) north of the French Riviera city of Nice. French and German accident investigators were heading for the crash site in Meolans-Revel, a remote and sparsely inhabited commune, not far from the Italian border.

German Chancellor Angela Merkel said she would travel there on Wednesday. Germanwings and the Catalan regional government were preparing to take Spanish relatives to the site.

Family members arrived at Barcelona's El Prat airport, many crying and with arms around each others' shoulders, accompanied by police and airport staff.

In Llinars del Valles, the Spanish village that hosted the German schoolchildren, Mayor Marti Pujol said the whole village was distraught.

"The families knew each other," he told Reuters. "The parents had been to see them off at 6 this morning."

King Felipe and Queen Letizia of Spain called off their state visit to France in a sign of mourning for the victims. They had arrived in Paris minutes after the crash happened.

Airbus confirmed that the plane was 24 years old, having first been delivered to Germanwings parent Lufthansa in 1991. It was powered by engines made by CFM International, a joint venture between General Electric and France's Safran.