By Renee Maltezou and Harry Papachristou
ATHENS (Reuters) - Tens of thousands of Greek protesters rallied in Athens on Thursday in a general strike marked by clashes between rival groups demonstrating ahead of a vote in parliament on a painful new round of austerity measures.
The rally, which drew some 70,000 people, was interrupted by fighting between groups of black-clad youths and rivals from PAME, a communist-affiliated labour group, traditionally opposed to disruptive violence at demonstrations.
Police initially stood by but eventually moved in to confront rioters, firing tear gas at groups of protesters throwing rocks and masonry chipped off nearby buildings. At least 16 people were taken to hospital with injuries.
The clashes in front of parliament followed violence on Wednesday when groups of youths fought police at the start of a 48-hour general strike against the package of cuts and tax hikes demanded by the European Union and International Monetary Fund.
Deputies are expected to pass the plan late on Thursday after the bill secured a first vote on Wednesday.
As Prime Minister George Papandreou prepared to fly to Brussels where a meeting of European leaders on Sunday will try to agree measures to stem the debt crisis, ministers made a final plea to pass the bill and prove Greece's credibility.
"You have to approve the law, with all its clauses," Finance Minister Evangelos Venizelos told lawmakers.
"This is not a game. If anybody thinks they can test how much wiggle-room we have, they're mistaken."
Outside parliament, volunteer first aid workers treated a number of injured, some suffering from cuts to the head while occasional bangs from smoke and flash bombs rang out as police deployed and the main demonstration thinned out.
Health ministry officials said one man died of a heart attack on the fringes of the rally.
The head of the Greek Communist party, Aleka Papariga condemned the violence, which she said had been deliberately provoked by groups of "hood-wearers."
"This was a pre-meditated attack," she told reporters, saying the rioters served the interests of what she termed "specific mechanisms."
"No matter what happens, we're not leaving," she said. "There's no other way out, people have to take the situation into their own hands."
HOSTILITY
One rebel deputy was still holding out but two others bowed to pressure from party leaders who said agreement was needed to persuade lenders to release badly needed new funds and the bill was expected to pass with the government's majority of 154 seats in the 300-member parliament.
"I will vote in favour, but this is the last time -- I am struggling with my conscience," said Vasso Papandreou, a member of PASOK who is no relation to the prime minister.
"Enough is enough, society is despairing, the country is collapsing," she said to applause from other PASOK deputies.
The deep public sector pay and pension cuts, tax hikes and changes to sectoral wage agreements have roused deep hostility from many Greeks, who say it punishes the weak and will only drive the stricken economy further into the ground.
The general strike called by unions representing around half the Greek workforce is one of the largest protests since the start of the crisis two years ago and brought more than 100,000 people to the streets on Wednesday.
The mood remained hostile to both the government and the EU-IMF "Troika," which is expected to approve a new tranche of aid but which has pressed for tougher action from the government.
A spokesman for GSEE, the main private sector union, said strike levels had fallen somewhat on Thursday, as many cash-strapped workers, who lose pay for stoppages, returned to work but protesters said they were determined to continue.
"I will be protesting every day, it's a matter of survival. They must go," said 49-year old Yannis Zahariadis, a civil servant and father of four. "I was forced to borrow money from my mother, a pensioner, to make ends meet."
RECESSION
The violence, which appeared to be the work of a hardcore group of mainly younger protesters, overshadowed the strike that shut down much of the country and drew in Greeks from broad sections of society.
On Thursday, shops re-opened but ministries, schools, banks and other public buildings were shut, transport services severely restricted and hospitals running on skeleton staffing.
As the protests have continued, there has been widespread speculation the government will fall early, forcing a snap election before the scheduled date in 2013 but Papandreou has repeatedly ruled out stepping down early.
"People sent a message on Wednesday that they have reached their limits and can't take any more austerity," said Theodore Couloumbis of the ELIAMEP think-tank.
With Greece reeling from three years of recession and a mountainous public debt which has shut it out of bond markets, Papandreou's government is trapped between lenders demanding tougher action and growing public anger at the cuts.
There were smaller protest rallies in other cities across the country but the government vowed to push through the measures, which are needed to obtain the aid it needs to keep paying the country's bills.
"Today, we must arm the prime minister for negotiations that will decide if Greece can pay for wages and pensions, fuel and pharmaceuticals, whether it can continue as an EU member," Education Minister Anna Diamantopoulou told parliament.
(Additional reporting by Lefteris Papadimas and Dina Kyriakidou; Writing by James Mackenzie; Editing by Maria Golovnina)
