Germany has reiterated that Greece's bailout terms are non-negotiable, as the country attempts to form a new coalition government.
Greek voters decided to stick with the euro in an election which narrowly handed victory to the pro-bailout party, New Democracy.
But the centre-right party only secured 29.7% of the vote, meaning it has to cobble together a coalition to achieve a working majority in the 300-seat parliament.
The party's leader Antonis Samaras has met with President Karolos Papoulias, who asked him formally to try and assemble a government.
The outcome of the election provided respite to some EU leaders, but Germany has stressed that it expects the next Greek government to stick to the terms of its bailout agreement.
Chancellor Angela Merkel was the first European leader to phone and congratulate Mr Samaras, saying she would "work on the basis that Greece will meet its European commitments".
And Germany's foreign minister, Guido Westerwelle, reiterated the point.
"The substance of the reforms is not negotiable," he said.
"Whatever government is formed must stick to what has been agreed with Europe."
Mr Westerwelle added that his country was willing to discuss the time-frame of the austerity programme.
"Clearly time was lost with the election and we have to talk about what that means for the reforms," he said.
"We're ready to talk about the time-frame as we can't ignore the lost weeks and we don't want people to suffer because of that."
But other German officials, who did not want to be named, said these remarks of Mr Westerwelle's were not representative of the government's line.
Six weeks ago Mr Samaras attempted to coax political enemies into a government of 'national salvation' but failed.
Now the stakes are higher and the pressure greater, as markets around the world weigh in on the political drama.
If Mr Samaras is again unable to reach the number of MPs required to secure a solid majority within three days, the task will fall to the Syriza party - led by Alexis Tsipras - which received 26.9% of the vote, the second-highest vote tally.
In a victory speech in Athens, Mr Samaras called for a government of national unity.
"The Greek people voted today to stay on a European course and remain in the eurozone," he said.
"There will be no more adventures; Greece's place in Europe will not be put in doubt, the sacrifices of the Greek people will bear fruit."
Syriza's leader Mr Tsipras conceded defeat and said: "We will be here as the opposition, we represent a majority of people opposed to the bailout deal."
Greece's conservative party won 129 seats in the election and is expected to form a pro-bailout coalition with the socialist Pasok party, which won 33 seats.
If they form a coalition they would have a majority of 12 seats.
Pasok's leader, Evangelos Venizelos, said: "There is not one day to lose. There is no room for party games.
"If we want Greece to really remain in the euro and get out of the crisis to the benefit of every Greek family, it must have a government tomorrow."
The British Foreign Office said "the UK will work with whatever Greek government is formed".
And Prime Minister David Cameron, who postponed leaving for the G20 summit to see who won the election, said a "very bad crisis" had been avoided.
The leaders of Italy and Spain - two countries at the centre of fears over contagion in the debt crisis - welcomed the election result as good news for Europe.
Italy's prime minister Mario Monti said: "This allows us to have a more serene vision for the future of the European Union and for the eurozone.
"We hope that a strong government can be formed which confirms the commitments made with the EU."
While Spain's Mariano Rajoy described the outcome as "good news for Greece, very good news for the European Union, for the euro and also for Spain".
"I am totally convinced that this strengthens the euro," he added.
China also welcomed the outcome.
"We hope the election result can help stabilise the economy in the eurozone," a Chinese foreign ministry spokesman said.
But it "is not going to be easy" for a coalition government, Professor George Pagoulatos, who was a senior advisor to the former Prime Minister of Greece, said.
"They [will] aim for a government that would last at least for two years," he told Sky News.
"The Greek society has faced a near death experience over the last few weeks...
"I think they feel the weight of this near-catastrophe on their shoulders and they will try to do their best to put Greece on a sound footing.
"This will involve the continuing implementation of the programme and will also involve some serious renegotiation of any aspects of it that can be improved."
New Democracy is committed to keeping Greece within the euro and has vowed to negotiate with Greece's creditors to ease the bailout conditions and try to boost economic growth.
Syriza had promised to rip up the current agreement - a move many believed would force Greece to leave the eurozone.
The reaction of the financial markets to the outcome of the election will be closely watched, as fears by investors of a Greek exit from the eurozone look set to ease.
