One person has been arrested in connection to an arson attack on the offices of Hellas Gold at the Skouries gold mine in Halkidiki, northern Greece, on Sunday.

The 54-year-old man, a local resident, was arrested late on Sunday. Police said there is evidence linking him to the attack. It is thought that up to 50 people were involved in the raid, which led to a number of vehicles being burned.

Two guards were also tied up and doused with a flammable liquid, police said. The assailants are also alleged to have been carrying guns, which they fired into the air.

A total of 33 people were detained on Sunday, prompting residents of the nearby village of Ierissos to hold a public rally to protest what the saw as being random detentions by the police.

Sources said that police have collected evidence from the scene of the attack and are expecting the results of forensic tests. Officers have apparently gathered droplets of blood, a ski mask, cigarette butts, a torch and a surgical mask.

The Skouries mining project has been strongly opposed by some locals, environmental groups and political parties over fears of the lasting damage it could do to the local environment.

Hellenic Gold, which is 95-percent owned by Canadian Eldorado Gold, insists that the mine is legal and has all the necessary environmental permits.