At least 43 people, most of them pensioners on a day trip, have been killed in a head-on collision between a bus and a truck in south-west France.
The crash happened on a country road near Puisseguin in the Gironde wine region, east of Bordeaux. Both vehicles then caught fire.
France's president promised a full investigation into what he called an "immense tragedy".
It is the worst French road disaster since 1982, when 52 people died.
The bus collided with the timber truck at 07:30 local time, at what local residents described as a notoriously dangerous bend in the road.
Both vehicles quickly caught fire. Local people reported seeing a plume of smoke from several kilometres away.
Video on French television showed two blackened vehicles, with the bus facing the wood-transporter's trailer, its cab skewed to one side.
Prime Minister Manuel Valls, speaking from the scene, said the victims had died "in atrocious conditions".
"It's a terrible shock for France," he added.
Eight people survived, four of whom were in a serious condition.
Local MP Gilles Savary told RTL radio that one of the injured was a motorist who had stopped at the scene and tried to rescue people.
Regional officials said the bus driver had survived the crash but the lorry driver was among the fatalities.
The body of the lorry driver's three-year-old son was also found in the cabin of his vehicle.
Authorities have been quoted as saying that it could take up to three days to remove the dead from the bus.
The exact cause of the crash is unclear, but Puisseguin Mayor Xavier Sublett said the lorry driver had lost control leaving him "stranded in the middle of the road". The bus driver tried to avoid the lorry but was in collision with it, he added.
Other reports said the bus driver then managed to open the doors and get some passengers off the bus.
Most of those on board were members of an elderly people's association from the small town of Petit-Palais-et-Cornemps, which has a population of just 700, along with others from neighbouring communities.
They were at the start of their journey, and were heading south for a day trip into the Landes region.
Town councillor Jeremiah Bessard told the iTele channel that its residents had been hit hard by the news: "We all knew someone." The flags in Puisseguin have been lowered to half mast.
A resident of Petit-Palais-et-Cornemps told BFMTV: "It's as if our village had lost a whole generation."
President Francois Hollande said the government had "fully mobilised" to deal with the tragedy, and said he had been "plunged into sadness".