The tremors were reportedly felt “widely across Athens”.
The US Geological Survey confirmed the 4.4 magnitude quake struck 30 miles south-southeast of Patras.
Greek journalist Yannis Koutsomitis tweeted: “Strong #earthquake felt in Athens two minutes ago.”
The quake comes on the same night as thousands of anti-austerity protesters clashed with police outside the capital’s parliament building.
Demonstrators threw petrol bombs and stones at officers, who responded by firing tear gas at the crowd.
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