SEYNE-LES-ALPES, France: Germany’s interior minister said there was no reason to suspect foul play in the crash of a Germanwings airliner in France on Tuesday that killed all 150 passengers and crew.

Investigations would pursue all possible angles, Thomas de Maiziere told reporters on Wednesday. But he added: “There is no concrete evidence that third parties were involved in the causes of the crash.”

French President Francois Hollande, German Chancellor Angela Merkel and Spanish Prime Minister Mariano Rajoy arrived near the site of the crash in the French Alps.

The three leaders, looking sombre and dressed in black, met rescue workers and police outside the crisis centre set up in the wake of the disaster

Lufthansa said on Wednesday it could not explain why its airbus had crashed.

Investigators said the remoteness of the crash site meant it could be days before a clear picture emerged of the tragedy.

However they said the fact that debris was restricted to a small area showed the A320 was not likely to have exploded in mid-air, suggesting a terrorist attack was not to blame.

“It is inexplicable this could happen to a plane free of technical problems and with an experienced, Lufthansa-trained pilot,” Lufthansa chief executive Carsten Spohr told reporters in Frankfurt.

Lufthansa said the 24-year-old plane had on Monday had repairs to the hatch through which the nose wheel descends for landing. A spokeswoman said that was not a safety issue but that repairs had been done to reduce noise.

Police and forensic teams on foot and in helicopters investigated the site about 100 km north of Nice where the airliner came down en route to Duesseldorf from Barcelona.

“When we go to a crash site we expect to find part of the fuselage. But here we see nothing at all,” said pilot Xavier Roy, coordinating air operations. Roy said teams of investigators had been dropped by helicopter onto the site and were working roped together at altitudes of around 2,000 meters.

It would take at least a week to recover all the remains of the victims, he said.

No distress call was received before the crash, but French authorities said one of the two “black box” flight recorders, the cockpit voice recorder, had been recovered, albeit in need of repair.

“The black box has been damaged. We will have to put it back together in the next few hours to be able to get to the bottom of this tragedy,” Interior Minister Bernard Cazeneuve told RTL radio.

In all, 72 Germans were killed in the crash, the first major air passenger disaster on French soil since the 2000 Concorde accident just outside Paris. Spanish officials said 49 Spaniards were among the victims.

Other victims included an American, a Moroccan and citizens of Britain, Argentina, Australia, Belgium, Colombia, Denmark, Japan, Mexico, the Netherlands, and Israel, French officials said. However DNA checks to identify them could take weeks.