An Airbus A320 operated by the Germanwings flight 9525, a budget subsidiary of German carrier Lufthansa, crashed Tuesday in the French Alps, apparently killing all 150 people on board, including 16 high school students from Germany.
French Interior Minister Bernard Cazeneuve said a black box has been located at plane crash site. It wasn't immediately clear if the box had been recovered.
The Associated Press cited regional official Eric Ciotti as saying wreckage from the plane had been discovered at Meolans-Revels, near a popular ski resort between the towns of Digne-les-Bains and Barcelonnette. The wreckage was believed to be on the side of a mountain, inaccessible by roads and covered in heavy snow.
AFP quoted a police officer in the town of Le Vernet, near the crash site, as saying: "There is no need for any rescue operations, everyone is dead."
Germanwings said the plane, which had been en route from Barcelona, Spain, to Dusseldorf, Germany, was carrying 144 passengers, two pilots and four crew members. An airline executive said two babies were believed to have been aboard the flight and CBS News' Heather Bosch confirms with a school administrator that 16 students and two teachers from Joseph-Koenig-Gymnasium High School from the German town of Haltern were on the plane.
"This is, of course, the worst thing you could imagine," Haltern Mayor Bodo Klimpel said.
French Prime Minister Manuel Valls said that a helicopter landed near the area where the plane went down, but the crew found no survivors.
"It is going to take days to recover the victims, then the debris," senior police officer Jean-Paul Bloy told Reuters.
Gilbert Sauvan, president of the general council of the Alpes-de-Haute-Provence, told the Associate Press that "everything is pulverized" at the site of the crash.
"There is nothing left except debris and bodies" tweeted local deputy Christophe Castaner after flying over the crash site with Cazeneuve.
The airline's managing director Oliver Wagner said Germanwings would do everything possible to determine what brought Flight 9525 down, but that he had no information on what might have caused the crash as of Tuesday afternoon.
"Our deep sympathy goes out to the relatives and friends of the victims," Wagner said.
French President Francois Hollande said search and rescue teams did not expect to find any survivors from the crash.
"It's a tragedy on our soil," the French leader said. He spoke on the phone later Tuesday to his German counterpart Angela Merkel, as he expected many of the victims of the crash were German.
Speaking in Germany, Merkel said she would fly herself to the crash site on Wednesday "to talk with local authorities."
"We all feel deeply saddened and our thoughts are with victims, relatives and loved ones," added Merkel.
Officials said 67 German nationals were believed to have been on the plane.
A spokesman for Spain's Deputy Prime Minister Soraya Saenz de Santamaria said there were at least 45 people on the plane "with Spanish surnames," according to the Reuters news agency.
The U.S. was reviewing whether any American citizens were aboard the flight, according to State Department spokesperson Jen Psaki.
There was no immediate indication as to what might have caused the crash. Weather in the area was good at the time the plane went missing, but was taking a turn for the worst in the afternoon, raising fears that search and rescue efforts could be even further hampered.
The plane dropped from a normal cruising altitude of about 38,000 feet to just 10,000 or 11,000 feet in the space of only eight minutes before dropping off radar screens.
The plane never issued a distress call during its descent, France's aviation regulator said, according to Reuters.
"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 spokesman for the DGAC authority said.
Pierre Polizzi, who owns a campsite near the crash site, told The Associated Press he heard two long noises around the time the Germanwings plane went down.
"There are often fighter jets flying over, so I thought it sounded just like that. I looked outside but I couldn't see any fighter planes," he said. "The noise I heard was long -- like 8 seconds -- as if the plane was going more slowly than a military plane speed. There was another long noise about 30 seconds later."
French Interior Ministry spokesman Pierre-Henry Brandet said the jet crashed in the mountains at an altitude of about 6,550 feet. Crews were struggling to access the crash location due to the rugged terrain.
Brandet told BFM television that he expected "an extremely long and extremely difficult" search and rescue operation because of the area's remoteness.
Bernadette Meehan, spokeswoman for the National Security Council, said that President Obama had been briefed on the crash and U.S. officials have offered assistance to French, German, and Spanish authorities.
"There is no indication of a nexus to terrorism at this time," Meehan said.
Airbus told CBS News in a statement that the manufacturer was "aware of the media reports and all efforts are now going towards assessing the situation."
The Airbus A320 is a workhorse of the short and medium-haul passenger aviation business. More than 3,000 of them are in daily operation with airlines around the world.
Both Germanwings and its parent company Lufthansa have strong safety records.
Germanwings boss Thomas Winkelmann told reporters Tuesday that the ill-fated aircraft was last given a routine safety check the day before the crash in Dusseldorf, by Lufthansa technicians. The last major maintenance check was conducted in the summer of 2013, in line with the proscribed timetable.
Winkelmann said the pilot in charge of flight 9525 had more than 10 years experience in the air, including more than 6,000 flight miles logged on Airbus aircraft.