French soldiers inspect the crash site of Air Algerie flight AH5017, near the town of Goss, north of Bamako in Mali. The second black box was removed from the site of the crash.

AFP

France said on Monday the pilots of the Air Algerie passenger plane that crashed in Mali, killing all 118 people on board, had asked to turn back, in a new development to a tough probe into the tragedy

"What we know for sure is that the weather was bad that night, that the plane crew had asked to change route then to turn back before all contact was lost," Foreign Minister Laurent Fabius told reporters in his latest briefing about Thursday's disaster.

It had previously been known that the crew asked to change route due to bad weather conditions, but the revelation they then demanded to turn back is a new development.

Speaking hours after the black box flight recorders of the McDonnell Douglas 83 jet arrived in Paris from Mali to help investigators, Fabius added air crash experts on the remote desert site of the accident were toiling away in "extremely difficult conditions".

France's transport minister, meanwhile, warned that analysing the crucial black boxes that record flight data and cockpit conversations could take "weeks".

Fabius said that more than 20 air accident experts were in Mali's remote, barren Gossi area where the plane came down, working in tough conditions to determine why the plane plunged into the ground and to try and recover remains of the victims.

"The (human) remains are pulverised, the heat is overwhelming with rain to boot and with extreme difficulties in communicating and in transport," he said at the foreign ministry, where the flag flew at half-mast in mourning for the tragedy that saw entire families wiped out.

Video footage of the Gossi area showed a scene of devastation littered with twisted and burnt fragments of the plane.

Meanwhile, black boxes from the crash arrived in Paris.

Flags on government buildings in the French capital and elsewhere in the country flew at half-mast in mourning for the victims of last Thursday's tragedy that saw entire families wiped out.

Thousands of kilometres away on the remote desert site of the accident, experts were sifting through the remains of the aircraft to try and determine why it plunged to the ground with such force that it almost completely disintegrated.

"I can confirm that the two flight records of the MD-83 (McDonnell Douglas 83) that crashed in Mali arrived this morning at the Bureau of Investigations and Analyses," a spokeswoman for the agency that probes air accidents said. "At this stage, we cannot say anymore."

According to a source close to the case, who refused to be named, one of the black boxes - devices that record flight data and conversations in the cockpit - was badly damaged on the outside.

Depending on their condition, it can take anywhere from several hours to several days or weeks to get raw data from the black boxes.

Video footage of Mali's remote, barren Gossi area where the plane came down showed a scene of devastation littered with twisted and burnt fragments of the plane.

France bore the brunt of the tragedy, with 54 of its nationals killed in the crash of flight AH5017, which had taken off from Ouagadougou in Burkina Faso and was bound for Algiers.

Travellers from Burkina Faso, Lebanon, Algeria, Spain, Canada, Germany and Luxembourg also died in the accident that has tentatively been blamed on bad weather that forced the pilots to change course.

On Monday, several towns across France that lost entire families or couples to the tragedy announced they would pay homage to people they held dear.

The central village of Menet, where a family-of-four perished in the crash, said a silent march would take place Friday in front of the places where the victims used to go, such as the school or certain shops.

"People in the village can't quite realise what happened. For us, the footage we see on television is extremely violent," said the mayor Alexis Monier.

In Paris, President Francois Hollande held another crisis meeting on Monday morning with ministers at the presidency, where the national flag flew at half-mast.

Paris has taken the lead in the probe, and Hollande has said the bodies of all passengers on the plane - not just French nationals - would be repatriated to France.

The accident is the worst air tragedy to hit France since the crash of the Air France A330 from Rio de Janeiro to Paris in June 2009.

It was also the third crash worldwide in the space of just eight days, capping a disastrous week for the aviation industry.

On July 17, a Malaysia Airlines plane was shot down in restive eastern Ukraine, killing all 298 people on board.

And a Taiwanese aircraft crashed in torrential rain in Taiwan on Wednesday, killing 48.

MH17 black boxes: Crash ‘caused by rocket shrapnel’

Black boxes recovered from downed Malaysia Airlines flight MH17 in rebel-held east Ukraine show shrapnel from a rocket explosion caused the passenger jet to crash, a Ukrainian security official said on Monday.

International investigators "indicated that data from flight recorders show that the reason for the destruction and crash of the plane was massive explosive decompression arising from multiple shrapnel perforations from a rocket explosion," Andriy Lysenko, spokesman for Ukraine's National Security and Defence Council, said.  

Data from the doomed airliner's black boxes was decrypted in Britain after being handed over to Malaysian officials by pro-Russian rebels controlling the crash site of MH17.

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