A report has emerged suggesting one of the pilots on the Airbus 320 that crashed in the French Alps had been locked out of the cockpit.
One hundred and fifty people were killed when Germanwings Flight 4U 9525 crashed on Tuesday.
The New York Times has reported that an unnamed investigator, who heard data in a black box recorder recovered from the aircraft, said the pilot left the cockpit.
The report also cited a senior military official.
The paper quoted the investigator as saying, "The pilot knocks lightly on the door, but gets no answer, he knocks louder, and finally there is a noise indicates the shut-out pilot is 'trying to smash the door down'."
The plane is said to have hit the ground in the French Alps at great velocity, suggesting no explosion in flight.
The plane, which was flying from Barcelona to Duesseldorf, crashed after what is now believed to be an 18 minute descent on Tuesday.
Recovery efforts scuppered by weather
Recovery teams have taken over a large part of this valley on the outskirts of town.
One van with sirens escorted a white trailer bearing the words "Mobile Criminal Investigation Laboratory", the BBC reported.
Some personnel are being lowered down by helicopters, a slow process made slower by strong winds.
Emergency workers in fluorescent jackets said that they wanted to work as quickly as they could.
"We cannot leave the victims a week in the mountains," said Roy Xavier, from Civil Security.
But victims' families will have a long wait for the bodies to be returned to them. Marseille's prosecutor told reporters that it may be several weeks before all the victims were identified, the BBC reported.
Germanwings chief Thomas Winkelmann said 72 of the 144 passengers killed in the crash were German citizens. The victims included 16 pupils returning from an exchange trip. Spain's government now says 51 of the dead were Spanish.
UK Foreign Secretary Philip Hammond confirmed that three Britons were on board. Other victims were from Australia, Argentina, Iran, Venezuela, the US, the Netherlands, Colombia, Mexico, Japan, Denmark and Israel.
However, there may be some duplication because of dual citizenship.