Athens - Riots erupted across central Athens on Sunday night shortly before a parliamentary vote on a vital international aid deal to avoid a Greek financial meltdown in March.
A dozen or so buildings and bank branches were torched and stores looted.
MPs from all parties have strongly condemned the violent acts, as local television channels broadcast images of historical buildings housing cinemas and offices in flames. There were no reports of people trapped inside.
In a statement, Athens Mayor Yorgos Kaminis said police had prevented unknown rioters from storming the City Hall and expressed his anger at the vandalism.
According to police sources and local media, dozens of people were slightly injured during extensive clashes between hooded protesters and police.
The scuffles, the worst in several months, broke out at the end of a mass anti-austerity demonstration of workers unions and Leftist parties in front of the parliament, as authorities had deployed some 5 000 policemen in Athens.
Minor incidents took place in other Greek cities where protesters attacked offices of local politicians and clashed with anti-riot police.
Despite the images of "chaos", Greek lawmakers are expected to seal in the early hours of Monday the agreement that will open the way for the release of a second multi-billion euro rescue loans package to Greece in coming weeks.
The new round of painful austerity policies attached to the deal under pressure by lenders, have fuelled anger amongst ordinary Greeks struggling with record high unemployment rates and heavy recession since late 2009, when the debt crisis started.
A Greek bankruptcy could cause social upheaval in the country and destabilise the entire Eurozone, officials have warned.
