A man died during violent clashes in Athens as 40,000 strikers pitted themselves against riot police on the streets of the Greek capital.

Petrol bombs hurled by protesters exploded at the feet of police who returned fire with tear gas and baton charges.

Officials say the 65-year-old died of a heart attack but local media is reporting that he was tear-gassed.

greek riots

Union leaders claimed 80,000 people attended the march but official figures are closer to 40,000

The country's 20th general strike in two years has been called in Greece to coincide with a meeting of EU leaders in Brussels.

Greeks are demonstrating against further austerity measures imposed by the EU and International Monetary Fund (IMF), as the near-bankrupt country struggles to secure a 13.5bn-euro (£11bn) bailout fund.

Without a bailout, Greece will run out of money next week.

grek riots

Greece is trying to secure bailout funding from the EU and IMF

Five years of recession have taken their toll on the population and many feel that any further wage and pension cuts will ruin the country.

A quarter of Greece's workforce is already unemployed.

Tania Karayiannis, of at ADEDY, a civil servants' union, told the Guardian: "Greeks are becoming increasingly conscious of what is happening.

"The political leadership of this country should not under-estimate that.

greek riots

It is the 20th strike in two years

"If they don't take our opposition seriously they will bear historic responsibility for the disintegration of Greece's social fabric and the developments that will surely follow."

Many fear that austerity may be manifesting itself in the rise of far-right political groups such as Golden Dawn which currently has 18 seats in the Hellenic Parliament.

The 24-hour strike, instigated by the country's two biggest labour unions, ADEDY and GSEE, has ground most of the business and public sector to a halt.

"I am here to ensure that the measures won't go through and because I feel Greek people should have a say on what is being done," a demonstrator told CNN.

"There is no other way. The only way is for the working class to understand that we must change things. That what is happening is a result of a flawed system. And we must make sure that it stops to exist."

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  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw petrol bombs at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw petrol bombs at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Protesters throw petrol bombs against riot police during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Riot police chase protesters during clashes during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Petros Giannakouris)

  • Riot police try to avoid petrol bombs thrown by protesters during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • A protester, background, clashes with riot police as a trade union member tries to calm other demonstrators during a 24-hour nationwide general strike in Athens, Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • Riot police clash with protesters during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Kostas Tsironis)

  • Protesters throw a petrol bomb at riot police during clashes during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Kostas Tsironis)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw petrol bombs at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Riot police are seen through tear gas during clashes during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Kostas Tsironis)

  • Petrol bombs explode in front of riot police during clashes during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Kostas Tsironis)

  • A protester shouts slogans during a rally during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Kostas Tsironis)

  • A Riot policeman pushes an elderly protester with his shield during clashes during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Petros Giannakouris)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-DEMO

    A fireboomb explodes near riot police during clashes with demonstrators during a 24-hour strike in Athens on October 18, 2012. Greek riot police fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit. The protesters had broken through a police line outside luxury hotels on central Syntagma Square and scattered groups of youths later attacked police with stones and firebombs, an AFP reporter said. AFP PHOTO / ARIS MESSINIS (Photo credit should read ARIS MESSINIS/AFP/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters shout at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: A protester protects herself from tear gas in front riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw stones at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    A man walks next to riot police forces during a protest march marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    Police stand amid tear gas during a protest march marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)

  • A protester with a mask and a Greek flag is seen during clashes during the 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Kostas Tsironis)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: A protester in shock afther police used tear gas and a shock bomb during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters protect themselves from tear gas used by riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw petrol bombs at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: A protester wears a Guy Fawkes mask in front of the Greek Parliament bulding during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    A man holds a placard in front of riot police forces during a protest march marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    Police clash with protesters during a rally marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    Police stand guard near a protester during a rally marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / ARIS MESSINIS (Photo credit should read ARIS MESSINIS/AFP/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    Police stand guard near a protester during a rally marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / ARIS MESSINIS (Photo credit should read ARIS MESSINIS/AFP/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters protect themselves from tear gas used by riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw petrol bombs at riot police officers in front of Greek Parlament during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • Greece Crippled By General Strike

    ATHENS, GREECE - OCTOBER 18: Protesters throw petrol bombs at riot police officers during a 24-hour nationwide general strike on October 18, 2012 in Athens, Greece. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble today as yet another Greek anti-austerity demonstration descended into violence. (Photo Milos Bicanski/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    A protester holds a placard in front of riot police forces during a rally marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / ARIS MESSINIS (Photo credit should read ARIS MESSINIS/AFP/Getty Images)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-STRIKE

    A firebomb explodes in front of riot police forces during clashes with demonstrators during a rally marking a 24-hour general strike on October 18, 2012 near the parliament in Athens. Greek riot police on Thursday fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / ARIS MESSINIS (Photo credit should read ARIS MESSINIS/AFP/Getty Images)

  • GREECE-FINANCE-ECONOMY-PUBLIC-DEBT-STRIKE

    A woman hides in a corner after clashes erupted between demonstrators and riot police during a 24-hour general strike on October 18, 2012. Greek riot police on October 18 fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit in Brussels. AFP PHOTO / LOUISA GOULIAMAKI (Photo credit should read LOUISA GOULIAMAKI/AFP/Getty Images)

  • Riot police try to avoid a petrol bomb in Athens, during a 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • GREECE-FINANCE-PUBLIC-DEBT-EU-DEMO

    A demonstrator clashes with riot police during a 24-hour strike in Athens on October 18, 2012. Greek riot police fired tear gas to disperse protesters at an anti-austerity rally in Athens held during a national general strike as EU leaders were to tackle the eurozone crisis at a summit. The protesters had broken through a police line outside luxury hotels on central Syntagma Square and scattered groups of youths later attacked police with stones and firebombs, an AFP reporter said. AFP PHOTO / ARIS MESSINIS (Photo credit should read ARIS MESSINIS/AFP/Getty Images)

  • A protester clashes with riot police during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Protesters clash with riot police during a 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Protesters throw petrol bombs at riot police officers during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Protesters clash with riot police in Athens, during a 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Protesters clash with riot police in Athens, during a 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Protesters throw petrol bombs against riot police during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Riot police try to avoid petrol bombs thrown by protesters during clashes during the 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Petros Giannakouris)

  • A riot policeman kicks away a tear canister in Athens, during a 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Greece was facing its second general strike in a month Thursday as workers protested over another batch of austerity measures that are designed to prevent the bankruptcy of the country. (AP Photo/Thanassis Stavrakis)

  • Protesters throw petrol bombs against riot police during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • Riot police try to avoid petrol bombs thrown by protesters during clashes during the 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Petros Giannakouris)

  • Protesters prepare to throw petrol bombs against riot police during a 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • A protester, background, clashes with riot police as a trade union member tries to calm other demonstrators during a 24-hour nationwide general strike in Athens, Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • A protester clashes with riot police during a 24-hour nationwide general strike in Athens on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • Riot police try to avoid petrol bombs thrown by protesters during a 24-hour nationwide general strike, Athens, Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Nikolas Giakoumidis)

  • Riot police kick a tear canister back at protesters during clashes during the 24-hour nationwide general strike on Thursday, Oct. 18, 2012. Hundreds of youths pelted riot police with petrol bombs, bottles and chunks of marble Thursday as yet another Greek anti-austerity demonstration descended into violence. (AP Photo/Petros Giannakouris)