Riots have broken out in the Greek capital Athens, and in the northern city of Thessaloniki, in the run-up to the first anniversary of the death last year of a 15-year-old boy.

In Athens, over 6000 police were deployed to prevent unrest. They fired tear gas at masked rioters who broke loose from a 3000 strong protest march and started breaking shop windows and setting vehicles on fire. Around 40 people were arrested. In Thessaloniki, protesters clashed with more than 3000 police, who were unable to prevent a coffee bar being set on fire.

The police had been deployed to prevent a repeat of the riots that erupted after Alexandros Grigoropoulos was shot dead by police in the central Athens neighbourhood of Exarchia in 2008. His death led to weeks of violence in Athens and several other cities and caused millions of euros worth of damage. Two police officers were later charged with the murder of Mr Grigoropoulos; their trial is scheduled to begin in early 2010.

Despite this, a new socialist government has vowed to crack down on troublemakers and said it would not accept a repeat of last year’s violence. On Saturday, Athens police raided a youth centre where they made 20 arrests and seized gas masks, clubs and Molotov cocktails. Elsewhere in the capital, police arrested at least 150 other young people for preparing to riot and for setting cars on fire.

Photo of Athens police removing a protester by EPA