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Police mounted a strong presence for the summit in the secluded Greek resort of Porto Carras

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About 10,000 demonstrators gathered to protest against issues from anti-globalisation to environmental concerns

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However hostility soon erupted between the two sides

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Some protesters removed barbed wire from a nearby beach in order to march

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Fighting erupted between police and different groups of protesters. Greek Communist Party members clash with riot police

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Police used tear gas in an attempt to disperse angry demonstrators...

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... some of whom responded with force, here a protester kicks a police officers riot shield

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And both sides were engulfed as police tried to maintain order