Athens - In the latest of a series of attacks, rioters set fire to a local train in a posh Athens suburb, destroying three of six carriages, Greek news reports said Tuesday.

The protestors, who wore carnival masks and shouted anarchist slogans, threw firebombs into the ISAP local train when it arrived at its terminal station at Kifisia, a wealthy suburb of Athens, late Monday, Greek television said.

The few remaining passengers fled the station in panic. No one was injured, the reports said.

Greece has been caught in a spiral of violence over the past months. In the last weeks, unidentified rioters injured a police officer and attacked a police station and a television station.

Two underground leftist organizations took responsibility for the attacks, announcing the formation of an "urban guerrilla" force in Greece. Small anarchist groups firebomb cars or banks almost on a daily basis. (dpa)