Tens of thousands of outraged Greeks took to the streets Wednesday to protest harsh new spending cuts aimed at saving their country from bankruptcy, as workers walked off the job in a 24-hour nationwide general strike.

Clashes broke out the northern city of Thessaloniki and in the capital, where demonstrators chanting "thieves, thieves" attempted to break through a riot police cordon guarding Parliament and chased the ceremonial guards away from the Tomb of the Unknown Soldier in front of the building. Police responded with volleys of tear gas and stun grenades.

The demonstrations in Athens were some of the largest in recent years, with some estimates putting the crowd at about 60,000 people. Government officials put the number at above 25,000. Violence also broke out in Thessaloniki, where another 20,000 people marched through the city center, with youths smashing windows of stores and fast food restaurants.

Prime Minister George Papandreou on Sunday announced draconian austerity measures, including cuts in salaries and pensions for civil servants, and another round of consumer tax increases, to pull his heavily indebted country away from the brink of default.

Union reaction until now had been relatively muted by Greece's volatile standards, although the country has been hit by a series of strikes. The opposition conservatives — whom Papandreou's Socialists have blamed for mismanaging the economy and fudging statistics during their five years in power — trail the Socialists by 10 percentage points in recent opinion polls.

But anger has mounted after the announcement of new austerity measures, which were essential to unlock a 110 billion euro ($142.29 billion) rescue package in loans from other eurozone countries and the International Monetary Fund.