Austria has arrested an Iraqi on suspicion he sabotaged trains in Germany last year, prosecutors said Wednesday.

Italy's foreign ministry summoned Austria's ambassador on Tuesday after Vienna said it was considering introducing border controls to block migrants from passing between the two countries.

Austria's Freedom Party conceded defeat Sunday in its bid to elect Europe's first far-right president, as projections showed its candidate Norbert Hofer lagging behind in a bitterly fought election re-run.

Austria's Norbert Hofer won Friday another shot at becoming the European Union's first far-right anti-immigration president after the country's highest court dramatically annulled May's closely fought election result.

Austria's anti-immigration Freedom Party filed Wednesday a legal challenge after its candidate narrowly lost out on being elected the EU's first far-right president, alleging "terrifying" irregularities.

"We are not sore losers. This is about protecting the very foundations of democracy... The extent of irregularities is more than terrifying," FPOe leader Heinz-Christian Strache told a news conference in Vienna.

Asylum seekers to the European Union should be held on islands rather than be allowed direct access to the continent, Austria's foreign minister has said.

Sebastian Kurz suggested in an interview with Die Presse newspaper published Sunday that the bloc follow the "Australian example" to discourage migrants from setting out on the often perilous journey to Europe.

Austria's far-right is probing "countless" cases of fraud in last week's presidential election that saw its candidate lose by a narrow margin, the party chief was quoted as saying Sunday.

"We are going to get the countless indications (of irregularities) looked at by an independent, neutral body and then decide" whether to challenge the result, Freedom Party (FPOe) head Heinz-Christian Strache said.

Fans affectionately call him "the professor" or "Sascha", a diminutive of Alexander in reference to his Russian roots, while his critics decry him as a haughty "green dictator".

Instead of healing Austria's political rift, Alexander Van der Bellen has proved as divisive a figure in the country's nail-biting presidential race as his far-right rival.

Austria's Norbert Hofer narrowly failed Monday to become the EU's first far-right president, after his ecologist rival scraped victory in a knife-edge election that was a rude wake-up call for the continent's established parties.

The interior minister said that Alexander Van der Bellen won 50.3 percent of the vote in Sunday's election, compared to 49.7 percent for Hofer, presented as the friendly and moderate face of the anti-immigration, populist Freedom Party (FPOe).

Austria on Tuesday appointed Christian Kern as its new chancellor, with the ailing centrist government pinning its hopes on the ex-railway boss to help stem the surge of the far-right.

"You are taking on a great and beautiful but also difficult role with a lot of responsibilities," said President Heinz Fischer as he swore in Kern at Vienna's Hofburg palace.