Paris, March 25 (IANS): A day after a low-cost German Airline's aircraft crashed in the French Alps with 150 people on board, a probe into the accident was launched on Wednesday. The leaders of Germany, Spain and France visited the crash site.

Flight 4U9525, an Airbus A320 jet operated by Germanwings, the budget carrier of Germany's Lufthansa airlines, crashed on Tuesday in Alpes-de-Haute-Provence in the southern French Alps on Tuesday, killing all 150 on board -- 144 passengers and six crew members.

Earlier on Wednesday, search and rescue operations resumed at the crash site after bad weather halted the work on Tuesday night.

One of the black boxes -- the flight data recorders -- of the aircraft was recovered near Digne in France on Tuesday. Officials said it was damaged, but was still expected to yield data.

"At least some information would be recovered after the examination of the damaged cockpit voice recorder, which records conversations and noises in the cockpit," The Local reported, citing French Interior Minister Bernard Cazeneuve speaking to French radio RTL.

Transport Minister Alain Vidalies said if voices had been recorded, the investigation would proceed "fairly quickly".

A search for the second black box of the plane was still on.

French President Francois Hollande, German Chancellor Angela Merkel and Spanish Prime Minister Mariano Rajoy visited the crash site on Wednesday and thanked the rescue workers for their efforts, according to a BBC report.

Rajoy, who termed the crash a "dramatic and sad news with enormous human loss" on Tuesday, has declared three days of national mourning in Spain.

Germanwings chief Thomas Winkelmann said 72 of the 144 passengers were German citizens, according to a BBC report. The German victims included 16 school students returning from an exchange trip. Xinhua reported 49 of the passengers were from Spain.

British Foreign Secretary Philip Hammond confirmed that three Britons were also on board the ill-fated plane, BBC reported. Other victims were believed to be from Australia, Argentina, Iran, Venezuela, the US, the Netherlands, Colombia, Mexico, Japan, Denmark, Morocco and Israel.

The plane began descending one minute after it reached its cruising height and continued to lose altitude for eight minutes, Germanwings managing director Thomas Winkelmann told reporters.

He said the aircraft lost contact with French air traffic controllers at 10.53 a.m. at an altitude of about 6,000 ft.

Media reports indicated that the jetliner was one of the oldest in Germanwings' fleet and had served for over 24 years. It had flown to Barcelona from Duesseldorf earlier on Tuesday before meeting with the accident on the return flight.

The US said there was no evidence so far of a terror angle, BBC reported. A Lufthansa official said they were assuming for the time being that the crash had been caused by an accident.

"For the time being, we say it's an accident, anything else would be speculation," said Heike Birlenbach, a top official of Germanwings' parent company Lufthansa.

Birlenbach said the Airbus A320 had passed its last routine check on Monday and could not explain why it took off 20 minutes late.

"Only if those checks are ok, aircrafts are allowed to fly," Birlenbach added.

French MP Christophe Castaner, who flew over the crash site, tweeted: "Horrendous images in this mountain scenery."

"Nothing is left but debris and bodies. Flying over the crash site with the interior minister -- a horror -- the plane is totally destroyed."

The plane has been obliterated, with no piece of debris larger than a "small car", said Gilbert Sauvan, the president of Alpes de Haute Provence region in southern France, where the plane crashed, according to a CNN report on Tuesday.

The first Germanwings flight on the same route as the crashed plane took off from Barcelona on Wednesday morning, but the flight number had been changed to 4U9441.

Bereaved relatives of the victims of the crash started to gather at the Barcelona and Dusseldorf airports on Wednesday and a team of 30 psychologists was on hand to offer support and counselling.

Germanwings and Lufthansa have set up a free hotline with number 0800-11335577 for families of passengers involved for care and assistance.