ATHENS (Reuters/AFP) - Police fired teargas and clashed with youths Wednesday as tens of thousands protested in Athens, Thessaloniki and other main Greek cities against austerity measures to tame a public debt crisis. The clash began in Athens after a group of 50 young demonstrators were seen trying to approach a row of luxury hotels on central Syntagma Square. As police fired teargas to push them back, another 250 people according to authorities broke apart from the main body of demonstrators to throw stones and a few firebombs at officers, as the protest began to melt away in disarray. Two photographers were injured in the process and three people arrested. Some 20 shops in the surrounding area had their windows smashed, police said. The demonstrations drawing around 27,000 people in Athens and 7,000 in the second city of Thessaloniki, according to police estimates, were held amid a general strike that shut down Greece. The Socialist government meanwhile hit back at European criticism of Greeces fiscal management, accusing European Union partners of double standards and poor leadership. The 24-hour general strike grounded flights and disrupted services but stopped short of bringing Greece to a standstill. Scuffles broke out on the fringe of the protest, with police firing teargas to disperse groups of stone-throwing youths. Schools, government offices and courthouses were all closed while there was also major disruption to public transport, banks, hospitals and state-owned companies. Athens metro and bus lines did run a skeleton service to allow strikers to get to the street demonstrations. The main archaeological sites and museums, including the Acropolis in Athens, shut their doors as well. The General Confederation of Greek Workers (GSEE), which represents around a million members, said participation in the strike was close to 100 per cent in many areas of work. Today, from all locations in the country, a strong message of unity, struggle and protest is being sent, GSEE chairman Yiannis Panagopoulos said in a statement. The protesters were joined by the General Secretary of the European Trade Union Confederation (ETUC), John Monks, who said: The European Union should do more to help Greece. For the time being they are threatening to withdraw their support and this could create an anti-EU sentiment among Greeks, he warned. Many of those who stayed away from work joined the demonstrations against the government, which is trying to raise revenue through new taxes and save money through public sector benefit cuts and hiring freezes. Some protesters carried signs calling on the authorities to tax the rich instead and noted that the strike was also targeting speculators after a run against Greek bonds that has sharply pushed up the countrys borrowing costs. Others marched with banners criticising the plutocracy. The ADEDY civil servants union, whose 300,000 members are seen as the main target of the cost-cutting drive, were at the vanguard of the strike action, which was also backed by the national journalists union.