A Germanwings Airbus A320 passenger plane carrying 148 people crashed Tuesday in mountainous southeastern France, French Prime Minister Manuel Valls told reporters.

Valls said he fears those aboard the flight from Barcelona, Spain, to Dusseldorf, Germany -- 142 passengers and six crew members -- may be dead.

The plane crashed near Digne les Bains, in the Alpes de Haute Provence region, Valls said. French President Francois Hollande said survivors were not expected.

\"The conditions of the accident are not yet clear but lead us to believe there will be no survivors,\" Hollande said.

The twin-engine Airbus A320s, which entered service in 1988, is generally considered among the most reliable aircraft, aviation analyst David Soucie said.

The crash site would be nearly halfway between Barcelona and Dusseldorf. Crashes mid-flight are rare, as most happen near takeoff or landing, CNN aviation analyst Mary Schiavo said.

TM & © 2015 Cable News Network, Inc., a Time Warner Company. All rights reserved.