Riot police used tear gas and pepper spray against several hundred demonstrators after the violence broke out near the country's parliament. Protesters also set fire to trees in the National Gardens and used hammers to smash paving stones and marble panels to use as missiles against the riot police.
About 50,000 people joined the union-organized march in central Athens on Wednesday, held during a general strike against newausterity measures planned in the crisis-hit country. The action, the first large-scale walk-out since the country's coalition government was formed in June, closed schools and disrupted flights and most services.
Everyone from shopkeepers and pharmacists to teachers, customs workers and car mechanics joined the demonstration, seen as a test of public tolerance for more hardship after two years of harsh spending cuts and tax hikes.
"People, fight, they're drinking your blood," protesters chanted as they banged drums.
As the strike got under way Wednesday, Greece's prime minister and finance minister hammered out a €11.5 billion ($14.87 billion) package of spending cuts demanded by the country's international lenders.
Greece's politicians have struggled to come up with more austerity measures that would be acceptable to its rescue creditors, with disagreements arising between the three parties that make up the coalition government. The country has been dependent on international loans from other eurozone countries and the International Monetary Fund since mid-2010. Without them, Greece would be forced into a chaotic default on its debts and possibly into an exit from the 17-country bloc that uses the euro.
The country's lenders have demanded more fiscal reforms if they are to continue issuing more rescue payouts. The next payment of €31 billion hinges on the government agreeing to further cuts.
Finance Minister Yannis Stournaras and Prime Minister Antonis Samaras formulated a deal on the new €11.5 billion austeritypackage for 2013-14, along with another €2 billion in improved tax collection, a finance ministry official said Wednesday morning.
The other two party leaders were to be briefed by Samaras on Thursday, a party official said. Both spoke on condition of anonymity because they were not authorized to speak on the record.
Wednesday's strike shut down the Acropolis, Greece's most famous tourist site, and halted flights for hours. Ferry services were suspended, schools, shops and gas stations were closed and hospitals were functioning on emergency staff.
One of those striking was Athens hospital worker Alkis Betses, who has seen his monthly salary fall from €1,300 to €800 (($1,680 to $1,035), says new cuts will bring it down to €600 ($775).
"How can you survive on 600 a month, with ever-rising taxes, and continue to pay bills and buy necessary supplies?"
Betses said hospitals have been hard hit by spending cuts, with staff shortages and long delays in doctors' overtime pay for night shifts.
"The resentment has been there for long before the new measures. Imagine what will happen when they're made public," he said.