Athens, Greece (CNN) -- Thousands of people marched through Athens Thursday as part of a 24-hour nationwide strike to protest further austerity measures by the embattled government.





The strike began at midnight and caused all government-run institutions -- including schools, airports, trams, subways, and most buses -- to close down. Banks and the media were also shut, meaning no broadcast news Thursday and no newspapers Friday.





There were small clashes with police and protesters threw two petrol bombs at officers in Constitution Square, in front of the Parliament building. Police fired some tear gas and pepper spray in return, but otherwise the march was relatively calm.





Sixteen people were arrested and two police officers were injured, police told CNN. Many people appeared to be suffering from the tear gas.





The protesters are angry about further government measures aimed at cutting Greece's massive deficit. They oppose the cutting of benefits and salaries, and the raising of taxes, and want more of the measures to be aimed at the wealthy.





The government says Greece has to modernize its tax structure as the country suffers from tax avoidance and other structural impediments to job growth.





But younger workers say they already pay high taxes, have little job security and make less money than older generations.





Some of the same measures prompted large demonstrations and some violence two weeks ago, but polls at the time still showed the majority of Greeks backing the government plans.





Since then, government has introduced a third round of austerity measures in Parliament amounting to $6.5 billion of cuts and tax increases, and that has caused support for the government to slip -- polls now show only a bare majority in favor of the government's actions.





The Greek government revealed late last year that its budget deficit was 12.7 percent of its gross domestic product, far exceeding the European Union limit of 3 percent. Countries participating in the EU must agree to that condition and other economic goals.





Greece aims to reduce that deficit to 8.7 percent this year and reach the EU target by 2012.





Thursday's strikes were rescheduled from March 16, when European Union officials plan to go to Athens and assess Greece's financial pledges to Europe. Protesters moved the strikes to Thursday in order to maximize disruption, because both public and private sector workers would be able to strike.





The Greek government has said it will not back down in the face of strikes.





CNN's Jim Boulden contributed to this report.
Who were angry about the measures How many petrol bombs were thrown? When did strikes begin What began at midnight? When did the strike begin? What was thrown at officers What was the amount of austerity measures?
The protesters two at midnight The strike midnight two petrol bombs $6.5 billion
question: Who were angry about the measures, answer: The protesters | question: How many petrol bombs were thrown?, answer: two | question: When did strikes begin, answer: at midnight | question: What began at midnight?, answer: The strike | question: When did the strike begin?, answer: midnight | question: What was thrown at officers, answer: two petrol bombs | question: What was the amount of austerity measures?, answer: $6.5 billion