A British man will appear in a Greek court on Monday, to face charges of throwing petrol bombs during last week's European Union summit.
Both sides were engulfed in tear gas as police tried to maintain order
The 30-year-old, who has not been named, was one of 104 people detained on Saturday, the final day of the three-day summit in Porto Carras.
The British consul in Athens, Donald Holder, said: "The man was allegedly caught throwing these Molotov cocktails at riot police and allegedly having several in his rucksack. That doesn't look too
Mr Holder said the man had been taken to hospital after badly hurting his arm.
He will appear before magistrates in the city of Thessaloniki, about 75 miles from Porto Carras.
The man could be given bail or may face imprisonment, Mr Holder said.
A second Briton - a woman - is also believed to have been arrested during the demonstrations but she is not thought to have been charged.
Greek police said a total of 12 foreigners were arrested, including an American, a Cypriot, two Austrians, two Spaniards and a Syrian.
They said 85 explosive devices, clubs, masks and hammers were among the items confiscated from the suspects, after being found in the area of Saturday's disturbances.
Rioters attacked police with petrol bombs and rock-filled sacks during the disturbances.
Police responded with tear gas against the self-proclaimed anarchists, who poured out of university campuses - which the authorities are prohibited from entering under Greek law.
Efforts by shopkeepers to protect their stores with metal sheets and wooden panels were in vain.
A total of 30 stores - including a McDonald's restaurant - were damaged and four completely destroyed.
Also damaged were the local offices of Greece's Communist Party, bus stations, banks and cars.
The attacks came despite the presence of some 15,000 police, soldiers and coastguard officers at the summit, on the Halkidiki peninsula.