French scientists say it might be Europe's best set of dinosaur tracks

French fossil hunters have discovered huge dinosaur footprints, said to be among the biggest in the world.

The footprints were made about 150 million years ago by sauropods - long-necked herbivores - in chalky sediment in the Jura plateau of eastern France.

The depressions are about 1.5m (4.9ft) wide, corresponding to animals that were more than 25m long and weighed about 30 tonnes.

French experts say the find at Plagne, near Switzerland, is "exceptional".

"The tracks formed by the footprints extend over dozens, even hundreds, of metres," the National Centre for Scientific Research (CNRS) said.

The 30-tonne dinosaurs may have looked like this

"Further digs will be carried out in the coming years and they may reveal that the site at Plagne is one of the biggest of its kind in the world."

The footprints, from the Upper Jurassic era, were found in April this year by a pair of amateur fossil hunters, but have only now been authenticated by scientists.

Another layer of sediment, now rock-hard, had preserved the footprints. They were revealed when local tree-felling exposed the earth underneath, French media report.

The region was near a shallow, warm sea at the time the sauropods lived there.