Athens, Greece (CNN) -- Thousands of Greek public sector workers began a 48-hour strike Tuesday against planned cuts in government spending.
An estimated 2,000 protesters representing teachers from the public sector marched past the finance ministry and parliament, according to local police.
In central Athens protesters threw plastic bottles and sticks at riot police, says CNN producer Erin Mclaughlin, who said that about 200 retired Greek workers also took to the streets Tuesday.
In another demonstration members of the Communist Party of Greece (KKE) erected large banners near the Parthenon -- one read "People of Europe Rise Up."
Workers are demonstrating against tough planned austerity measures to meet European Union and International Monetary Fund conditions on a €110 billion ($146 billion) aid package
The protests come ahead of a planned nationwide general strike on Wednesday when public and private sector workers, including teachers, lecturers, bank employees and doctors, will go on strike.
According to a Ministry of Finance spokesperson, the austerity bill has been tabled before parliament, where it will be debated Wednesday.
The debates can take up to three days, so a vote is very unlikely before Friday at the earliest, said the spokesperson.
Finance Minister George Papaconstantinou announced tough cost-cutting measures Sunday in order for Greece to secure its financial lifeline.
The package includes a promise by Greece to cut its budget deficit to 3 percent of gross domestic product, as required by European Union rules, by 2014, according to Papaconstantinou.
Greece had a choice between "destruction" and saving the country, and "we have chosen of course to save the country," Papaconstantinou said.