Athens, Greece (CNN) -- Protesters and police clashed in front of the Greek parliament building Wednesday, as tens of thousands of demonstrators gathered in Athens on the first day of a two-day general strike over austerity measures.
Strikers in Greece aim to shut down wide sectors of the country, a day before lawmakers vote on a new round of tough cost-cutting measures.
"Don't bow your head, it's time for resistance and struggle," marchers chanted in the capital as numbers swelled for the union-backed demonstration.
The violence broke out around lunchtime in one corner of Syntagma Square, beside Parliament House, as protesters dressed mostly in black threw rocks and Molotov cocktails at police.
Officers fired stun grenades, tear gas and "flash bangs" in return, sending noisy detonations echoing round the square.
Smoke filled the area by mid-afternoon as a fire burned in front of the finance ministry, forcing many peaceful demonstrators to move away.
Police earlier estimated that more than 70,000 people were protesting in Athens, and said they planned to put between 2,500 and 3,000 officers on the streets. Organizers put the turnout at some 120,000 people.
Initially, most of the protesters gathered peacefully in front of Parliament House waving union flags, red flags and banners.
"I'm here for my children and everyone else's children. Those punks in there have destroyed everyone's lives," said former railway worker Diamandis Goufas, 62, pointing at parliament.
Greeks are angry at yet another round of planned austerity measures as Greece tries to bring down its stratospheric debt.
Lawmakers are trying to cut government costs to reassure international backers it is doing enough to earn the bailout funds they have promised to pour into the country, with more austerity measures expected to pass Thursday.
The new bill would lead to around 30,000 job losses and further cuts to wages and pensions for workers in the public sector.
That has left at least some Greeks furious at the countries demanding that Greece bring down its spending.
"We are not lazy; it's the Germans, they want to take our blood," said Eleftherios Zarkados.
At least one student said Wednesday that Thursday would not mark the end of the battle between politicians and the public.
"We will continue to resist even if the measures pass," said Sophia Titou, 21, a law student who works at an oil refinery.
Many on the streets say they are angry that the well-off people they believe are benefiting from corruption and tax evasion are not being pursued, while public sector workers pay the price for Greece's woes.
European Union leaders are scrambling to minimize the effect of Greece's debt on their common currency, the euro.
Over the weekend, finance ministers from the world's largest economies pledged their commitment to take "all necessary actions" to stabilize markets.
They aim to keep banks well capitalized so they can weather the effects of any defaults by Greece or other indebted countries like Portugal, Spain, Ireland or Italy.
But there appears to be a split between France and Germany -- Europe's two largest economies -- on how to do it.
Germany has stressed that individual European states should inject capital into domestic banks that lack sufficient buffers. But analysts say France is opposed to this idea because it could jeopardize the nation's top-tier credit rating.
European leaders are expected to hear concrete details about how the plan might work at a European Council meeting Sunday.
European Union heads of state are widely expected to finalize the plan in early November at a meeting of the Group of 20 world economic powers.
