A gang allegedly responsible for the plunder and sale of thousands of archaeological items has been arrested and suspected booty including Roman and Stone Age pieces seized, police said Friday.

The gang operated with metal detectors at sites throughout Spain, often selling their finds on the Internet, police said in a statement.

Among the locations plundered were archaeological digs at Calpe on the eastern Mediterranean coast and Municipium Augusta Bilbilis near Calatayud in central Spain, where the Romans built a colonial city on an even earlier settlement.

Agents searched 24 addresses, arrested 20 suspects and needed three vans to carry away suspected loot from one of the places searched, the statement said.

Roman swords, a statue of a she-wolf suckling Romulus and Remus, 12,000 coins, stone and metal axes and more than 10,000 paleontological pieces were among the artifacts seized, police said.