Violent protesters attacked peaceful ones with petrol bombs and stones on Thursday in Athens, as tens of thousands rallied outside parliament ahead of a vote on despised new austerity measures demanded by creditors to keep the country afloat.

As the second day of a general strike paralyzed the country, more than 50,000 peaceful demonstrators flooded downtown Syntagma Square, the scene of violent protests on Wednesday, the first day of the nationwide strike.

Creditors have demanded the extra austerity measures before they give Greece more funds from a euro110 billion ($152 billion) bailout loan from other eurozone countries and the International Monetary Fund. Greece says it will run out of money in mid-November without the next euro8 billion ($11 billion) instalment.

The austerity bill won initial approval from the Greek parliament, and deputies on Thursday were voting on the details, which include putting 30,000 public servants on reduced pay and suspending collective labour contracts.

The demands have enraged ordinary Greeks. Communist party supporters taking part in the Thursday's rally set up a cordon in front of parliament to prevent hard-liners from starting fights with police.

But they came under repeated attacks by hundreds of masked protesters in motorcycle helmets who threw gasoline bombs and chunks of marble into the crowd. Fights broke out as the Communist party supporters went on the counterattack. Chaos ensued as protesters and masked youths armed with clubs charged each other, and riot police fired volleys of tear gas in an attempt to separate the two sides.

At least ten people were treated by medics, mostly for facial cuts, but two had serious head injuries.

The violence came a day after a massive Athens demonstration by more than 100,000 people also degenerated into a riot, with masked, black-clad protesters attacking riot police, who responded with volleys of stun grenades and tear gas.

The next instalment of the bailout for Greece has yet to be authorized and there's growing unease in the markets about whether a summit of eurozone leaders this Sunday in Brussels will yield a comprehensive solution to the continent's debt crisis, which has seen Ireland and Portugal bailed out as well as Greece. Finance ministers from the 17 countries that use the euro will meet ahead of the summit on Friday.

The Greek government's latest round of austerity measures are expected to pass, although dissent from governing Socialist party deputies could further weaken Prime Minister George Papandreou's slim majority in Parliament, where he holds 154 of the legislature's 300 seats.

Greece's international creditors, meanwhile, warned that a second rescue package tentatively agreed in July may not be enough to save the country from bankruptcy, according to a draft of a debt inspectors' report obtained Thursday by The Associated Press in Berlin.

Although the inspectors said Greece has missed its deficit-cutting targets and that the pace of its reforms is insufficient, they said Athens should get euro8 billion ($11 billion) of bailout loans as soon as possible so the country does not default on its debts next month.

Greece has been relying on a euro110 billion ($152 billion) package of rescue loans since May last year. In July, eurozone leaders tentatively agreed in a second euro109 billion ($150 billion) bailout, that would also see banks and other private bondholders give Greece easier terms on its debt.

However, the inspectors from the European Commission and the European Central Bank said Greece's debt dynamics remain "extremely worrying."

The conclusions pile pressure on European leaders to make private creditors like banks take more losses on the Greek bonds they hold.

In Athens, Finance Minister Evangelos Venizelos issued an impassioned appeal to Socialist and opposition lawmakers alike Thursday, warning that failure to approve the measures would be disastrous.

"If the law is not approved, including every single article it contains—particularly those that (Greece's creditors) and eurozone members regard a symbolic and political necessity—there is no need for me even to go to the eurogroup meeting on Friday, or the prime minister to Sunday's summit," he said.

"The country will be exposed to the danger of a non-rational development, and will once again serve as the scapegoat on which Europe's historic, political and institutional shortcomings will be dumped," Venizelos said.

Unions seemed resigned to the law being passed, but warned that the whole country virulently opposed it.

"It looks as if (lawmakers) may be set to vote in favor of the new austerity law," said Ilias Iliopoulos, secretary general of the Adedy civil servants' union. "Our European friends must know that our prime minister will go to the European summit naked, because the promises he will make have no backing in his country."

The general strike Thursday disrupted public transport and left ships docked at ports. Schools and customs offices closed and state hospitals were running on emergency staff. All public services were shut, and even lawyers and prison guards were among those staying away from work.