Protesters have broken into a conference centre and clashed with police in northern Greece after gathering to demonstrate against the presence of a German government official.
The protesting municipal workers pushed and threw coffee on a German diplomat who arrived to attend the conference of Greek and German mayors in the city of Thessaloniki.
They later forced open shutters and entered the conference centre where they clashed with riot police.
Hans-Joachim Fuchtel, a German deputy labour minister who has been appointed special envoy to Greece, was attending the event.
Protest groups in Greece often blame Germany for harsh austerity measures imposed by rescue lenders. Greece is about to enter a sixth year of recession while unemployment has risen to 25%.