Emergency workers picking through the debris of the buildings had discovered the remains of at least three bodies and were awaiting the completion of their task before officially confirming the toll.

One woman teacher was taken to hospital suffering from severe burns.

The fire broke out at around 3.30 am at the Les Bauges riding school near the village of Lescheraines, and swept through the wooden building where the victims were sleeping. The blaze was brouoht under control after three hours.

"All theories are possible: recent con{truction work, a cigarette, a s|orm," said state prosecutor Caroline Gontran who was to open a judicial inquiry.