French Prime Minister Manuel Valls sought to reassure Chinese concerns about the eurozone, insisting that Greece will stay part of the single currency.
The White House said it was "monitoring closely" events in Greece, where a new hard-left government has vowed to reopen the terms of a massive financial bailout.
Greece has created a new headache for the EU by questioning sanctions against Russia over Ukraine.
The White House said it hoped to work closely with Greece's new government after the radical left-wing Syriza party stormed to power on an anti-austerity platform.
The International Monetary Fund said it was prepared to continue its financial support of Greece.
Greece awoke to a new era of defiant anti-austerity after voters handed a decisive victory to radical left party Syriza.
Russian President Vladimir Putin congratulated the leader of Greece's radical left-wing party Syriza on its decisive election victory.
France's President Francois Hollande congratulated Alexis Tsipras on his radical left party Syriza's victory in Greek elections Sunday.
Antonis Samaras is a late convert to austerity whose penchant for risky politics could now cost him his job.
IMF chief Christine Lagard warned of "consequences" if European countries try to renegotiate their debts, ahead of Greek elections.
Greek Prime Minister Antonis Samaras used the deadly Islamist attack on France's Charlie Hebdo magazine in an election campaign speech.
EU Economics Affairs Commissioner Pierre Moscovici said Greek voters will be left free to choose their destiny in upcoming elections.
French President Francois Hollande urged Greece to abide by its European commitments, as the spectre of a Greek exit from the eurozone rears its head again.
German Chancellor came under fire over a magazine report suggesting she would be prepared to let Greece exit the euro should a far-left party win a snap Greek election.
An election win for Greece's far-left Syriza party could cause political contagion across Europe by boosting support for other populists.
The International Monetary Fund said it was suspending talks on a new disbursement of financial aid to Greece until a new government is formed after elections.
Greece's parliament will try to elect a president on Monday in a last-ditch bid to avoid snap general elections that could bring the hard-left to power and spark new concerns over the eurozone economy.
The Greek public doesn't want a new adventure, Prime Minister warned as he sought to stave off a snap election by urging lawmakers to choose a new president.
A 5.2-magnitude earthquake struck northern Greece early, the country's earthquake observatory said, with no reports of victims or major damage.
Greek Prime Minister Antonis Samaras won a parliamentary confidence vote, which he called in a bid to rally support.