Almost 700,000 postal votes will determine if EU gets first far-right president

The direct votes gave Mr Hofer 51.9% to 48.1% for Mr Van der Bellen, a Greens politician who is running as an independent. But final projections that included still-to-be-counted absentee ballots put each at 50% with Mr Van der Bellen narrowly ahead.

The absentee ballots will be counted on Monday, making them the likely decider by a minuscule portion of votes, considering that 4.48 million people voted directly on Sunday.

Candidates backed by the long-dominant Social Democratic and centrist People's Party were eliminated in last month's first round, which means neither party would hold the presidency for the first time since the end of the Second World War. That reflects disillusionment with the status quo and their approach to the migrant crisis and other issues.

But Sunday's voting revealed a profound split over which direction the nation should now take, particularly over migration and the future of the European Union.

Mr Van der Bellen's supporters back liberal refugee policies and a strong, unified EU. Mr Hofer's Freedom Party wants closed borders and campaigns consistently on strong anti-EU sentiment within the country.

Both men drew clear lines between themselves both during the campaign and as they voted on Sunday.

Asked as he arrived to cast his ballot what differentiated him from Mr Hofer, Mr Van der Bellen said: "I think I'm pro-European and there are some doubts as far as Mr Hofer is concerned."

Mr Hofer, in turn, used his last pre-election gathering to deliver a message with anti-Muslim overtones.

"To those in Austria who go to war for the Islamic State or rape women - I say to those people, 'This is not your home'," he told a cheering crowd on Friday.

On Sunday, Mr Hofer sought to soothe international fears that he is a radical far-righter. The Austria Press Agency quoted him telling foreign reporters that he is "really OK" and "not a dangerous person".

Still, with the elections reverberating beyond Austria's borders, such assurances are unlikely to have much weight. A Hofer win would be viewed by European parties of all political stripes as evidence of a further advance of populist Eurosceptic parties at the expense of the establishment.

In Austria, the result could upend decades of business-as-usual politics, with the two candidates serving notice they are not satisfied with the ceremonial role for which most predecessors have settled.

Mr Van der Bellen says he would not swear in a Freedom Party chancellor even if that party wins the next elections, scheduled within the next two years.

Mr Hofer has threatened to dismiss Austria's government coalition of the Social Democrats and the People's Party if it fails to heed his repeated admonitions to do a better job - and is casting himself as the final arbiter of how the government is performing.

The constitution gives the president the right not only to sack the government but also to dissolve parliament. Still, both men are likely to avoid open confrontation, even if they occasionally stray from the usual ceremonial functions associated with the office, such as greeting incoming ambassadors, cutting ribbons and giving rubber-stamp approvals of new governments.

Political scientists suggested as much.

"The president can function only if he cooperates with the government," said Anton Pelinka. "I therefore see any outcome as having major atmospheric but less immediate political significance."

Peter Filzmaier said both would tone down their messages if elected, because "if they constantly take positions without being able to enact their views, they will soon have the image of a ranting heckler who cannot accomplish anything politically".

At the same time, Mr Hofer as president may be unwelcome in some European capitals as governments there try to keep their populist Eurosceptic parties in check. And the Freedom Party's anti-Muslim campaigning also could result in Middle East governments avoiding him.

It would not be a first for Austria. President Kurt Waldheim, who was backed by the centrist People's Party, was boycotted internationally decades ago after revelations that he served in a German unit linked to wartime atrocities.

Even with the vote still undecided, Mr Hofer worked on Sunday to lessen any negative international fallout should he be declared the victor.

He said the international community would soon realise that reports that he was on the far-right extremist fringe "do not jibe with the facts".