The tusks were well preserved (pic: Prof Evangelia Tsoukala, 2007)

A Dutch scientist at the site, Dick Mol, says the find near Grevena should help explain why mastodons died out in Europe two to three million years ago.

The mastodon's tusks measure 5m (16.5ft) and 4m, Mr Mol told the BBC.

They are the longest tusks ever found on a prehistoric elephant-like animal. "It is spectacular," Mr Mol said.

Early humans ate mastodon meat (pic: by Remie Bakker)

Mastodons are thought to have first appeared about five million years ago and became extinct in North America about 10,000 years ago - much later than in Europe.

The animals were similar to woolly mammoths, but had tusks that pointed forwards, rather than spiralling upwards. Their teeth were also different.

The team of palaeontologists, including Professor Evangelia Tsoukala of Greece's Aristotle University in Thessaloniki (Salonica), began the excavation on 16 July and is planning to finish it on Wednesday.

Thigh bones and teeth were also dug up (pic: Prof Evangelia Tsoukala, 2007)

Various parts of the skeleton have been dug up, along with teeth.

The animal's height was about 3.5m at the shoulder and it probably weighed some six tonnes. The mastodon feasted on leaves, unlike the woolly mammoth, which grazed.

Eventually, the specimen will go on display at a museum in Milia.