Germanwings flight with at least 142 passengers and crew of six goes down in the Alps region, French sources say.

Germanwings Flight 4U9525 was on its way from Barcelona to Dusseldorf when it went down in southern France [Flightradar24.com]

An Airbus plane operated by GermanWings with at least 142 passengers, two pilots and four flight attendants on board has crashed in the French Alps region.

In a live briefing on Tuesday, French President Francois Hollande said it was unlikely that there were survivors, adding that the area of the crash was remote.

Hollande said it was probable that a number of the victims were German. It was not clear whether anyone on the ground had been hurt, he said.

“It’s a tragedy on our soil,” Hollande said.

Hollande “extended all his support” to German Chancellor Angela Merkel during a phone call, the French presidency said in a statement, while the German ambassador to France said she would visit the crash site in the southern Alps within hours.

Spanish Prime Minister Mariano Rajoy said in a statement that at least 45 Spanish passengers were believed to be onboard the plane.

‘A loud noise, then nothing’

The owner of a nearby camping site said he heard the plane come down. “There was a loud noise and then suddenly nothing. At first I thought it came from fighter jets that often hold drills in the area,” Pierre Polizzi told Al Jazeera.

“The plane crashed just 2km from here, high on a mountain,” Polizzi, owner of Camping Rioclar, said.

Eric Ciotti, the head of the regional council, said search-and-rescue teams were headed to the crash site at Meolans-Revels.

French TV reported that 240 local firefighters and three police squadrons were mobilised for the rescue effort.

“We do not yet know what has happened to flight 4U 9525. My deepest sympathy goes to the families and friends of our passengers and crew 1/2

— Lufthansa (@lufthansa) March 24, 2015

“…on 4U 9525. If our fears are confirmed, this is a dark day for Lufthansa. We hope to find survivors.“ Carsten Spohr 2/2

— Lufthansa (@lufthansa) March 24, 2015

La Provence , a regional newspaper, cited French civil aviation authorities for the number of people on board.

The airliner went down near Digne-Les-Bains in Alpes-de-Hautes-Provence.

Al Jazeera’s Jacky Rowland, reporting from Paris, said the mountainous terrain where the plane went down could complicate the rescue effort.

A French security source confirmed that the aircraft belonged to GermanWings, an affiliate of German airline Lufthansa, and was travelling between Barcelona and Dusseldorf.

The single-aisle A320 typically seats 150 to 180 people.

Germanwings, a low-cost airline, said it would hold a news conference at 1400 GMT at Cologne-Bonn airport in western Germany.

A map on Flightaware.com showed that the plane fell off the radar in the southern French Alps [Al Jazeera]