Black-clad demonstrators hurled stones and fire bombs at police in front of the Greek parliament on Wednesday as tens of thousands rallied for a nationwide general strike to coincide with a vote on painful new austerity measures.
For the first time since the outbreak of the crisis two years ago, protesters pushed up to the steps of the parliament building itself, setting fire to a sentry box occupied by the ceremonial guards who stand watch over the main symbols of the Greek state.
Prime Minister George Papandreou, trailing badly in opinion polls, has appealed for support from Greeks before parliament votes on the latest measures which include tax hikes, wage cuts and public sector layoffs.
The mood was furious among demonstrators, fed up after repeated doses of austerity and increasingly hostile to both their own political leaders and international lenders demanding ever tougher measures to cut Greece's towering public debt.
"Who are they trying to fool? They won't save us. With these measures the poor become poorer and the rich richer. Well I say: 'No, thank you. I don't want your rescue'," said 50-year public sector worker Akis Papadopoulos.
The boom of tear gas canisters fired by police rang out, and black clouds of smoke from petrol bombs hung over Syntagma Square, scene of violent clashes between police and demonstrators at anti-austerity protests in June.
The clashes overshadowed the start of a 48-hour strike which shut down government departments, businesses and public services, as well as shops and bakeries. Flights were cancelled.
Several injuries were reported, mainly from minor burns and cuts to the head. There were also serious clashes away from the scene of the main rally, which attracted more than 100,000 people, according to police estimates.
Inside parliament, there was a bitter tang of tear gas in the air as deputies debated the bill ahead of a vote later on Wednesday.
More than 7,000 police had been assigned to Athens to deal with anticipated trouble with hundreds in riot gear near parliament. They mostly stood their ground, without launching major charges on demonstrators.
Most of the violence appeared to be the work of a hard core group of younger demonstrators and as the violence continued, older members of the crowd moved away from the area directly in front of the parliament.
Wednesday's action comes as European Union leaders scramble to outline a new rescue package in time for a summit on Sunday that hopes to agree measures to protect the region's financial system from a potential Greek debt default.
"We are in an agonising but necessary struggle to avoid the final and harshest point of the crisis," Finance Minister Evangelos Venizelos told parliament. "From now and until Sunday were are fighting the battle of all battles."
Trapped in the third year of deep recession and strangled by a public debt amounting to 162 percent of gross domestic product which few now believe can be paid back, Greece has sunk ever deeper into crisis.
Papandreou's narrow four-seat majority is expected to be enough to ensure the austerity bill goes through, especially given possible support from a smaller opposition group.
But his ruling Socialist party's discipline is increasingly strained with one deputy resigning his seat in protest and at least two others threatening to vote against part of the package dealing with collective wage bargaining agreements.
After repeated rounds of austerity measures, protesters said new cuts would only drive the country deeper into the ground. Unions urged deputies not to pass the law.
"If they have any humanity, decency, sense of pride and Greek soul left, they must reject the bill," Nikos Kioutsoukis, a top official in private sector union GSEE which is leading the strike with its public sector counterpart ADEDY.
Speaking in parliament on Wednesday, Dimitris Reppas, minister for Administrative Reform, reflected the increasing sense of isolation among many in the ruling party, complaining he felt as though he had been thrown to the lions.
"In government, we often feel like ... we are in the Colosseum, fighting the debt monster while everybody else is just sitting in the stands, watching and commenting," he said.
A first vote takes place late on Wednesday on the overall bill, which mixes deep cuts to public sector pay and pensions, tax hikes, a suspension of sectoral pay accords and an end to the constitutional taboo against laying off civil servants.
A second vote on specific articles is expected some time on Thursday and only after that the bill becomes law.
International lenders, who are providing the funds Athens needs to stay afloat after it was shut out of bond markets last year, have expressed impatience at the slow pace of reform as Greece has slipped behind on its budget targets.
There has been growing talk that Athens should be placed under tighter supervision by EU authorities to ensure it meets its reform obligations.