Ten people, including five children, are known to have died after a fire broke out overnight on Friday at a residential block in near the French city of Lyon, local authorities said. Another 14 were injured, four seriously.
The Lyon and Rhone regional authority said the cause of the fire in the eastern suburb of Vaulx-en-Velin was not known at this stage.
Dozens of ambulances and fire crews were sent to the site after the alarm was raised shortly after 3am local time on Friday morning at a seven-storey block of flats.
French Interior Minister Gérard Darmanin, who headed to the scene, said the casualty toll was "definitive", adding that the dead children were aged between three and 15 years old.
An investigation would determine the cause, he said. The fire was brought under control.
Four people were seriously injured, while another 10 were more lightly hurt, the minister said. They included two fire officers, according to the prefecture.
Fire officers said the flames took hold on the ground floor before spreading to the floors above, trapping some residents in their flats while smoke invaded communal areas.
"It was horrifying," Mohamed, the cousin of a fourth-floor resident who managed to escape up the stairs with his two children, told AFP.
Neighbours heard screams and tried to save lives, according to testimony broadcast by BFM-TV.
Reaction to the fire, including messages of solidarity with the victims and their families, began to spread on social media.
The fire occurred in the Mas du Taureau district, which has been undergoing urban regeneration having long been identified as one of several deprived areas in the Lyon suburbs.
In the early 2000s, the city launched a €100 million programme to rethink what was designed to become an eco-district, to develop local shops and public transport.
Housing Minister Olivier Klein also said he was on the way to Vaulx-en-Velin, describing the casualty toll as "chilling".
"I am going to the scene this morning to be with the residents, the elected officials and the emergency services," Klein said on Twitter. He added that he had spoken to the mayor of the town, Hélène Geoffroy, "to assure her of the State's support".
Darmanin, the interior minister, added that he was in touch with President Emmanuel Macron over the disaster.