An Airbus plane operated by Lufthansa's Germanwings budget airline has crashed in southern France en route from Barcelona to Dusseldorf, police and aviation officials say.
French president Francois Hollande said he believed none of the 148 people on board the plane had survived.
"There were 148 people on board," Mr Hollande said. "The conditions of the accident, which have not yet been clarified, lead us to think there are no survivors."
He said there was likely to be a significant number of German victims.
He added: "The accident happened in a zone that is particularly hard to access."
French prime minister Manuel Valls told reporters the cause of the crash was unknown.
A spokesman for the DGAC aviation authority said the airplane crashed near the town of Barcelonnette, about 100 kilometres north of the French Riviera city of Nice.
The local La Provence newspaper said the Airbus A320 was carrying 142 passengers, two pilots and four cabin crew, citing aviation officials.
Debris from a crashed airliner was found near a French village, the interior ministry said.
Lufthansa's Germanwings unit said it was as yet unable to verify reports of the crash.
The crashed A320 is 24 years old and has been with the parent Lufthansa group since 1991, according to online database airfleets.net.
An Airbus spokeswoman said the company was trying to assess the situation after the crash reports.
Reuters
Germanwings plane crashes in southern France, 148 feared dead: officials - ABC News (Australian Broadcasting Corporation)
Tinfoilers, to your keyboards....