Thousands of dinosaur footprints dating back 210 million years have been found in a national park in northern Italy.

The footprints - some of which are up to 40cm (15in) in diameter - are aligned in parallel rows, and many show clear traces of toes and claws.

It is thought the dinosaurs were prosauropods - herbivores with long necks, small heads, and sharp claws.

I never would have imagined I'd come across such a spectacular discovery in the region where I live, said Milan-based paleontologist Cristiano Dal Sasso.

Last September a photographer spotted the footprints stretching hundreds of metres on a vertical mountain wall in the Stelvio national park, north-east of Milan.

In the Triassic period - between about 250 and 201 million years ago - the wall was a tidal flat, which later became part of the Alpine chain.

According to a press release from the Italian culture ministry, the area is remote and not accessible by paths, so drones and remote sensing technology will be employed instead.

The prosauropods, which could be up to 10m (33ft) long, walked on two legs but in some cases handprints were found in front of footprints, indicating that they probably stopped and rested their forelimbs on the ground.

The Stelvio national park is located in the Fraele valley by Italy's border with Switzerland, near where the Winter Olympics will take place next year.