The heads of Lufthansa and Germanwings paid their respects Wednesday near the crash site of the plane that slammed into the French Alps, after reports a video had emerged showing the final terrifying seconds in the cabin.
Carsten Spohr and Thomas Winkelmann's visit comes at a time of intense scrutiny on Lufthansa, which owns Germanwings and has revealed it was aware that the co-pilot suspected of deliberately crashing the airliner had suffered from severe depression.
Lufthansa said 27-year-old Andreas Lubitz had told the airline in 2009 about his illness after interrupting his flight training.
Flight 4U9525 crashed in the French Alps last week at a speed of 700 kilometres (430 miles) an hour, killing all 150 people on board.
Lufthansa's Spohr and Germanwings chief Winkelmann arrived at Seyne-les-Alpes near the crash site aboard a helicopter, later making their way to the village of Le Vernet where they laid a wreath at the foot of a memorial erected for the victims.
Spohr then read out a statement to reporters, but refused to answer a torrent of questions.
There are "no words to describe how terrible this accident is," he said, thanking rescue teams and locals for their support in the aftermath of the March 24 disaster and promising continued help for the victims' relatives.
The crash, which caused shock worldwide, continues to make headlines, with French and German media saying they have seen a video purportedly showing the final seconds inside the cabin of the doomed airliner, which they said was shot on a mobile phone.
"The scene was so chaotic that it was hard to identify people, but the sounds of the screaming passengers made it perfectly clear that they were aware of what was about to happen to them," said French weekly Paris Match.
People were heard crying "My God" in several languages, the magazine said.
Investigators say the plane's cockpit voice recorder indicated Lubitz locked the captain out of the cockpit and deliberately crashed the plane.
Paris Match said "metallic banging" could be heard more than three times -- tallying with reports that the pilot tried to smash down the cockpit door with an axe.
French police poured cold water on the magazine's footage claims, telling CNN the reports were "completely wrong."
Marseille prosecutor Brice Robin, one of the lead investigators into the crash, added that anyone with footage "must hand it over immediately to investigators".
Meanwhile, authorities were set Wednesday to start gathering the personal belongings of victims at the remote crash site.
In Berlin on Tuesday, French President Francois Hollande said authorities hoped identification of all 150 passengers would be possible within a week, though investigators have previously said it could take weeks and some may never be identified due to the extent of the devastation.
Some 450 relatives have visited the site so far, a local official said Tuesday.
Lufthansa said $300 million (280 million euros) had been earmarked to cover the damages, while Germanwings will immediately compensate each family with 50,000 euros -- a sum that will not be deducted from any final compensation deal.
The catastrophe has dealt a heavy blow to the image of Lufthansa, which announced Tuesday it would cancel celebrations next month to mark its 60th anniversary.
German prosecutors have said Lubitz was diagnosed as suicidal "several years ago", before he became a pilot, but had appeared more stable of late.
Doctors had recently found no sign he intended to hurt himself or others, but he was receiving treatment from neurologists and psychiatrists who had signed him off sick from work a number of times, including on the day of the crash.
Police found torn-up sick notes during a search of his apartment after the crash.
The plane's second black box, which gathered technical data on the flight, has yet to be found.
French investigators said Tuesday they would now concentrate on "the systemic weaknesses" that might have caused the disaster, including the logic of locking cockpit doors from the inside, which was introduced after the September 11, 2001 terrorist hijackings in the United States.
They also plan to look into procedures for detecting "specific psychologic profiles" in pilots.