The devastating rail crash that killed six people, as a train tore in half and careered into a busy station, was caused by a faulty rail track, according to French state rail.
The train was twenty miles south of Paris on Friday afternoon, destined for Limoges, when it derailed at Bretigny-sur-Orge. It is France's worst rail accident in 25 years.
And local media reported that some people had attempted to loot the train and steal from the injured by posing as rescue workers. Reports said some were throwing stones at emergency professionals, but the incidents were played down by the French transport minister, who said those responsible were arrested.
Rescuers help people on the site of a train accident in the railway station of Bretigny-sur-Orge
SNCF management said in a statement that the cause of the crash was a connector which had worked its way loose and become detached just 200m from Bretigny station, causing the train to derail.
It involves a kind of steel clip that connects two rails at a switching point which "broke away, became detached, removed from its position," according to Pierre Izard, general manager of infrastructure for SNCF.
Checks are being carried out to the entire rest of the network and the crash is also being investigated by legal authorities an France's safety agency BEA.
Six carriages derailed during the accident, and one mounted the station platform. Investigators are still picking through the wreckage, looking for those who may still be trapped.
Speaking on RTL radio, Transport Minister Frederic Cuvillier said the train driver had reacted quickly to the accident: "Fortunately, the driver of the locomotive had absolutely extraordinary reflexes in that he sounded the alarm immediately, preventing a collision with another train coming in the opposite direction and which would have hit the derailing carriages within seconds. So it is not a human error."
Cuvallier also said he had no reports of stealing from the injured or dying, apart from one isolated incident where a laptop was stolen and a man arrested.
Stones were thrown, he said, but they did not hit police, and those responsible have been arrested.
The scene at Bretigny-sur-Org
Le HuffPost, quoting a source close to the investigation, reported that five of the six bodies have been identified and freed from the debris of the train throughout the night.
The tragedy has caused widespread problems across the country, occurring in the run-up to Sunday's Bastille Day holiday weekend. A minute of silence will be observed at noon in all stations and trains on Saturday.
Graham Hope, a passenger on the train, told Sky News that the train "bounced up and down like a bucking bronco".
"It was bouncing for several seconds before we came to a halt. My carriage came to a halt in the station.
"Everybody was very calm, only a couple of people were quite concerned. We pulled together very well, organised ourselves to get out of the carriage.
"I got a minor head injury, just a gash on the top on my head and minor cuts. There was glass everywhere, in people's pockets.
"I was in the half of the train, the three carriages left behind when the train split in two. I looked down the line and you can see the rest of the train.
"I heard that the last carriage had no injuries, but the first carriage of the three left in the station was on its side, with a major hole in its side. I'd be surprised if people got out of their unscathed."
Foreign Secretary William Hague said in a statement: "I was shocked to hear about the serious train crash outside Paris. My thoughts are with the victims and their families.
"The British Embassy in Paris is in close touch with the French authorities and stands by to provide any assistance required.”
The Foreign Office told HuffPostUK it had no reports, as yet, of any British casualties.