Greek protesters have hung two giant banners from the Acropolis in Athens, with multi-lingual slogans calling for demonstrations across Europe.
One banner displayed Wednesday bore the word "resistance" in Greek, English, and several other European languages. The other called for demonstrations across the continent Thursday.
Protests are already planned in Athens and the northern city of Salonika Thursday, to protest the December 6 police shooting of an Athens teenager. Authorities say rioting triggered by the death is the worst in the country in decades.
Greek Prime Minister Costas Karamanlis said Tuesday the protests have damaged the country's economy.
Retailers have reported more than a billion dollars in damage and lost sales. Gangs of protesters looted, smashed, or burned hundreds of shops and banks during the 12 days of violence.