Six people have died and several dozens injured when a passenger train derailed and crashed into a station outside the French capital, Paris, the interior ministry said, adding the death toll could rise.
"The death toll is evolving constantly at this point and unfortunately it will probably rise," Interior Minister Manuel Valls said after the accident on Friday.
"At this stage there are six people dead, several dozen wounded; nine of them are in serious condition."
I heard a loud noise. A cloud of sand covered everything
The cause of the crash was under investigation. Two train cars, numbers 3 and 4, initially derailed, then knocked the other cars off the track, the head of the SNCF rail authority, Guillaume Pepy, said.
The SNCF said the train derailed at 5:15pm local time (1515 GMT) and crashed into the Bretigny-sur-Orge station.
The train - a regional service that travels more slowly than France's TGV express trains - veered off the track as it pulled into the station, about 26km south of Paris. It was en route from Paris to the city of Limoges.
"Most of the people who suffered minor injuries have been taken care of. We are going to have to empty the carriages completely to see if there are victims or not," said local politican Michel Pouzol.
Some cars slid toward the station, crushing part of the metallic roof over the platform. Images from the scene shown on French television showed gnarled metal and shards on the platform, and debris from the crash clogging the stairwell leading beneath the platform.
"I heard a loud noise. A cloud of sand covered everything," one witness, Bazgua El Mehdi, 19, who was on a nearby train, told Le Parisien newspaper.
The crash is the deadliest in France in years, and French President Francois Hollande abandoned plans in the capital to visit the scene.
Al Jazeera's Tristan Redman, reporting from Paris, said the head of the French railway company called it a "catastrophe".
"There are some gruesome reports coming out of people who were electrocuted or crushed in the wreckage. There are still some people believed to be stuck in the wreckage and until the rescuers can see what is under the wreckage the death toll can still rise," our correspondent said.
"There were at least 317 people on the train according to the head of the French railway who was down at the site.
"This evening is the start of the summer holiday for many people in France so it was one of the busiest evenings of the year on the roads and railways," Redman added.
Passengers who spoke to French media from the scene said it was travelling unusually fast as it approached the station.
TV images showed one of the carriages smashed against a platform at Bretigny-sur-Orge station.