Five children from the same family have died after the minivan they were travelling in crashed and caught fire in Drôme in south-eastern France.
The children were aged three to 14, reports French media.
Three adults and a seven-year-old child are in hospital in a serious condition following the accident on Monday evening.
French President Emmanuel Macron tweeted a tribute to the family.
"I share the immense pain of the relatives of the victims. My thoughts are also with those injured and all those who support them," Mr Macron wrote.
Des enfants ont perdu la vie ce soir dans un terrible accident routier dans la Drôme. Je partage la douleur immense des proches des victimes. Mes pensées accompagnent aussi les blessés et tous ceux mobilisés à leurs côtés.— Emmanuel Macron (@EmmanuelMacron) July 20, 2020
An investigation has been opened to establish if the incident was caused by a technical failure or lack of vehicle maintenance, according to French media.
At least 53 firefighters attended the scene of the accident, as well as three helicopters to transfer the survivors to a hospital in Lyon for patients with severe burns, reports France Bleu.
The nine family members, from the suburbs of nearby Lyon, were travelling in a minivan intended for seven people, Valence prosecutor Alex Perrin said.
It appears that the driver lost control of the vehicle after which it rolled over three or four times and caught fire, Mr Perrin said.
The intense blaze has made identification of the deceased children difficult, he added.
Before he lost consciousness, the driver told witnesses he had had difficulty braking, the prosecutor suggested.
Minister of the Interior Gérald Darmanin thanked the emergency workers who attended the scene.
"Strong emotion following the terrible accident on the A7 in Drôme. My first thoughts are with the victims and those injured," Mr Darmanin wrote.
Vive émotion suite au terrible accident survenu sur l’A7, dans la Drôme.— Gérald DARMANIN (@GDarmanin) July 20, 2020
Mes premières pensées vont aux familles des victimes et aux blessés.
Merci aux forces de secours qui sont mobilisées.
Avec @Djebbari_JB, nous nous rendons immédiatement sur place.
"Support and solidarity with our injured fellow citizens who are fighting for their lives," tweeted Prime Minister Jean Castex.