An international crime gang that ransacked ancient sites in southern Italy and trafficked stolen archaeological goods worth millions of euros has been broken up, Italian police say.

Key points: The crime gang looted sites across Italy, France, Britain, Germany and Serbia

The crime gang looted sites across Italy, France, Britain, Germany and Serbia Some of the sites date back to the fourth century BC

Some of the sites date back to the fourth century BC Police said "brutal" methods were used to break into the ground to recover the items

Police have conducted more than 80 searches across Italy, France, Britain, Germany and Serbia, arrested 23 people and recovered some 10,000 archaeological items.

The crime gang carried out illegal digs in areas where official archaeologists were yet to explore.

Police said they had been following the group since May 2017, using wire taps and video surveillance to see how the art treasures were found and then sold abroad.

"Significantly, images taken by drones show the violence of the clandestine digs carried out by this criminal gang, with a [mechanical] excavator used to break up the ground with enormous brutality," police said in a statement.

Items including terracotta vases, painted plates and jewels worth "several million euros" were taken. ( Supplied: Europol )

Among the areas ransacked were sites that dated back to the fourth and fifth centuries BC, when the coast of southern Italy was dotted with ancient Greek colonies.

The thieves walked off with terracotta vases, painted plates, brooches and jewels. Police said the stolen goods had a value of "several million euros".

Italian police said more than 10,000 historic items had been recovered. ( Supplied: Europol )

Middlemen who looked to sell the looted artefacts worked out of London, Munich, the French city of Dijon and Vrsac in Serbia.

Italy has a police unit dedicated to tackling art looters which led the operation.

Italian police used drones as part of their investigation into the looting. ( Supplied: Europol )

"Calabria is particularly rich in ancient heritage and is the object of incessant and intense plundering which feeds the clandestine market for art work," police said.

Reuters