One of the two pilots of the Germanwings plane that crashed in the French Alps was apparently out of the cockpit at the time, news reports said, citing officials involved in the investigation.

A spokesperson for Lufthansa, which owns the airline operating the ill-fated Airbus A320, said early today it had “no information that can confirm” the reports.

“At the start of the flight, you can hear the crew talking normally, then you hear one of the seats being moved back, a door opening and closing, and then the noise of someone knocking on the door,” a person with knowledge of the content of the recordings was quoted as saying by French news agency AFP .

The unnamed source was confirming a report late yesterday by the New York Times , which quoted a senior military official involved in the probe saying, “The guy outside is knocking lightly on the door, and there is no answer.”

“And then he hits the door stronger and no answer. There is never an answer,” the source was quoted as saying.

The AFP source said there was no further conversation heard after one of the pilots left the cockpit, adding it was not clear whether it was the captain or co-pilot.

Towards the end of the recording the alarm indicating ground proximity can be heard, the source said.

Search teams were set to continue their examination of the crash site in the French Alps today, hoping to find further clues as to what caused the crash and the remains of victims.

Flight 4U9525 left Barcelona around 10am (0900 GMT) on Tuesday, going into a descent and disappearing from radar around an hour later before crashing around kilometres north-west of the southern French town of Nice.

There were 150 people on the plane, including 72 Germans and 35 Spaniards.

- dpa