French president Francois Hollande has said that no survivors are expected in the French Alps plane crash carrying between 142 and 150 passengers.
"Solidarity must be our first sentiment," Hollande said speaking on French television. He added that the site of the German wings crash is a "very difficult area to access".
In a tweet, Hollande expressed solidarity with the families of the victims:
The aircraft, said to be an Airbus A320 from German low-cost airline Germanwings, came down in Digne, southern France, local media reports.
The French civil aviation authority said the crew sent a "very brief" distress signal at 10.47. A gendarmerie helicopter reportedly located the crash site in high mountains.
Captain Benoît Zeisser told BFM TV that the area of the crash was "very difficult to access", with areas of snow in the crash zone measuring between 500m and 2000m.
The flight was said to be between Barcelona in Spain and the German city of Dusseldorf, according to flight tracker service Airlive.
Some 148 people, passengers and crew, were said to be aboard flight 4U9525 as it disappeared from radars minutes after 9.30am UTC.
The crashed A320 is reportedly 24 years old and has been with the parent Lufthansa group since 1991.
Lufthansa CEO Carsten Spohr tweeted:
Spain's airport operator Aena said the missing Germanwings plane took off from Barcelona at 8.55am. The flight initially climbed to 38,000 ft (11,500m) before it started to descend and lost signal at 6,800 ft (2,072m) according to Flight Radar.
Eric Ciotti, the head of the regional council, said search-and-rescue teams were headed to the crash site at Meolans-Revels. The area is 15km from Barcelonnette, amid peaks of 2,900m.
Hollande said he is in contact with German Chancellor Angela Merkel as although the identities of the victims are not yet known, it is likely many are German nationals.
A local official told the New York Times that an initial survey of the area by helicopter "showed that debris had been spread over five acres of a very craggy area".
Germanwings blackened its Twitter logo following the crash: