Greek police fired tear gas as protestors threw firebombs, burnt dustbins and vandalised shops Wednesday at the start of a two-day strike ahead of a vote on a new austerity bill to stave off bankruptcy. Police in Athens clashed with protesters outside parliament as more than 70,000 people according to authorities, and 200,000 according to unions, converged on central Syntagma Square. At least 17 people including three civilians were hurt, among them an off-duty officer struck by unknown assailants who seized his service handgun, police said. Nearly 5,000 policemen were on alert in the capital. Tear gas blanketed central Athens as police fought to keep control on the square in front of the Greek parliament. Greek parliamentarians meanwhile adopted in first reading the new bill which introduces collective wage amendments, major tax break cuts, a new civil service salary system and temporary layoffs for thousands of public sector staff. During the largely procedural vote in the 300-member parliament, 154 lawmakers from the ruling socialist Pasok party voted in favour; 141 opposition lawmakers voted against, and five deputies were absent. Parliament is to hold a definitive vote on the controversial bill on Thursday, when more protests are planned for the capital and beyond. Wednesday\'s violence began when some 200 youths hurled firebombs and pieces of masonry hacked off from neighbouring buildings at police from behind a steel barricade erected outside the parliament. They vandalised shops, burnt dustbins and threw stones at the police. A battle later broke out outside a row of luxury hotels on the square and a department store was vandalised as small groups of hooded and masked protesters broke away from the main demonstration. A presidential guard sentry box was set on fire near the tomb of the Unknown Soldier, Greece\'s foremost military monument next to parliament. The attackers also pelted police with refuse littering the city\'s streets from a two-week strike by municipal garbage collectors, and smashed a police sentry box near the finance ministry. Officers were also attacked in the second city of Thessaloniki where the government\'s regional headquarters was assaulted by 100 protesters throwing firebombs. The bulk of demonstrators in Athens, Thessaloniki, Patras, Heraklion and other cities were peaceful despite boiling anger against the new wave of cuts imposed on a country already slogging through nearly two years of belt-tightening. \"I can either pay my taxes or feed my children, I cannot do both,\" said Sophia Robola, a 35-year-old woman employed at a store shutter company. A hundred of her colleagues were recently fired and she has not been paid in four months, she told AFP. \"People have to take to the streets to protest and clear the country of those who govern us and who no longer represent us,\" said Yorgos, an unemployed 50-year-old. State statistics this week showed unemployment climbing to 16.5 percent in Greece during a deepening recession. Unions say the real figure is much higher, and will hit 26 percent next year. Deputies \"should think twice and three times against what they are about to do to a people living through social barbarism\", warned Yiannis Panagopoulos, head of Greece\'s main union GSEE that represents the private sector. More protests were scheduled for Thursday, when leftist and Communist unions plan to encircle parliament. The government has repeatedly warned that failure to pass the legislation on Thursday ahead of an EU crisis summit on Sunday would prompt Greece\'s peers to block the release of loans and cause a payments freeze. Finance Minister Evangelos Venizelos told parliament on Wednesday that Greece faced a \"battle of battles\" in Brussels and would be unable to finalise its budget without Thursday\'s new measures. Another minister said Greece should still be able to hit its target of raising four billion euros ($5.5 billion) from sales of state assets this year. \"Selling state assets as quickly as possible is not an end in itself, even if we think it possible to meet the target of collecting four billion euros in 2011,\" Development and Competitiveness Minister Michalis Chrysohoidis told the French business daily Les Echos in an interview to be published Thursday.