The mayor of Athens says more than 60 stores have been damaged in the city's busiest shopping area following a violent protest organized by anarchist groups.

George Kaminis visited Athens' central Ermou Street early Tuesday, and said the violent protesters were trying to bring the city's commercial activity "to its knees."

Late Monday, dozens of youths carrying hammers and metal bars smashed storefronts before being dispersed by police who used tear gas. Thirteen people were detained for questioning and later released, and one other was arrested on unrelated charges.

The protest was sparked after an Athens court rejected a motion to suspend a sentence for a 29-year-old teacher who was convicted of being a member of militant anarchist group. More protests are planned later Tuesday.