The polls have opened in Greece for crucial elections which could determine the country's future in the eurozone.
The main contenders, the left-wing Syriza and right-wing New Democracy, are at odds over whether broadly to stick with the tough EU bailout deal, or reject it and boost social spending.
EU leaders say that to reject it would lead Greece out of the eurozone.
The poll, the second in six weeks, was called after a vote on 6 May proved inconclusive.
The BBC reports the vote is being watched around the world, amid fears that a Greek exit from the euro could spread contagion to other eurozone members and send turmoil throughout the global economy.
Tough austerity measures were attached to the two international bailouts awarded to Greece, an initial package worth €110 billion in 2010, then a follow-up last year worth €130bn.
Germany insists Greek must abide by austerity conditions
On the eve of the vote, German Chancellor Angela Merkel warned that it cannot renegotiate its bailout.
Mrs Merkel said on Saturday that Greece would not be allowed to dodge its austerity agreement.
Many Greeks are unhappy with the conditions attached to deals which have been keeping Greece from bankruptcy.
European leaders fear the poll could see Greece leave the euro currency if anti-austerity party Syriza forms a government.
Mrs Merkel warned any country against leaving the currency union believing the unity of the euro zone would be in danger if that happened.
"We will have to speak to any government. I can only warn everyone against leaving the currency union. The internal cohesion of the euro zone would be in danger," she said.