Politicians from Europe's mainstream parties called on voters to stand against the far right, after a video sting brought down the leader of Austria's Freedom Party (FPO), hurting the momentum of nationalists days before a European parliamentary election.

Austria's president called on Sunday for the country to hold a snap general election in September, seen as the quickest timetable possible, after the resignation of vice chancellor Heinz-Christian Strache brought down the ruling coalition.

Mr Strache quit on Saturday after video emerged showing him discussing fixing state contracts in return for financial and political favours with a woman posing as the niece of a Russian oligarch.

He accepted that the video was "catastrophic", although he denied breaking the law or following through on discussions.

Mr Strache's far-right Freedom Party, part of Austria's ruling coalition since 2017, has been one of the most successful groups among the anti-immigrant and nationalist parties that have surged across Europe in recent years.

The far-right politicians winning power across Europe Show all 7 1 /7 The far-right politicians winning power across Europe The far-right politicians winning power across Europe Viktor Orban – Hungary, Fidesz The Prime Minister of Hungary has threatened to shut down NGOs that help refugees; run a state backed hate campaign against George Soros and removed constitutional checks and balances. He said: 'We have replaced a shipwrecked liberal democracy with a 21st century Christian democracy' Reuters The far-right politicians winning power across Europe Matteo Salvini – Italy, Lega The leader of Italy’s junior governing party has pledged to deport 500,000 irregular migrants; stated joining the euro was a mistake and wants to end sanctions against Russia. He said: 'The only antidote to racism is to control, regulate and limit immigration' AFP/Getty The far-right politicians winning power across Europe Heinz-Christian Strache – Austria, FPO The deputy prime minister of Austria wants to drive Islam out of public life in Austria; has threatening mosque closures and wants to end sanctions against Russia. He said: 'Let us put an end to this policy of Islamisation as soon as possible' AFP/Getty The far-right politicians winning power across Europe Marine Le Pen – France, Front National The runner-up in the French presidential election wants policies to favour ‘native’ French; has stated she would hold an EU referendum and wants to deport irregular migrants. She said: 'I’m not offended when I hear President Donald Trump say "America first". In fact, I want America first for the American people, I want Britain first for the British people and I want France first for the French people' AP The far-right politicians winning power across Europe Janez Jansa – Slovenia, Slovenian Democratic Party The leader of Slovenia’s largest party says the country is run by a secretive former communist cabal; has appointed political allies to press agencies and was sent to prison for alleged corruption which was later overturned by the Constitutional Court. He said: 'Our party puts Slovenia, Slovenians first' Reuters The far-right politicians winning power across Europe Alexander Gauland – Germany, AfD The leader of the first far-right party in the Bundestag in decades says Islam is not a part of Germany; wants a ban on public Islamic symbols and wants to leave the euro. He said: 'A German or English football team hasn’t been German or English in the classical sense for a long time' Alamy The far-right politicians winning power across Europe Jarosław Kaczynski – Poland, Law and Justice The chairman of Poland’s governing party says migrants spread infectious diseases; wants to ban gay people from being teachers and has sought to implement constitutional changes to give government more power over courts. He said: 'It is absolutely clear a homosexual should not be a teacher' Kacper Pempel/Reuters

Mainstream leaders across the continent made clear they hoped his downfall would have an impact far beyond Austria in the 23-26 May vote for the European Parliament.

The Freedom Party is part of an alliance of European nationalist parties led by Matteo Salvini of Italy's League, who held a mass meeting in Milan on Saturday with Marine Le Pen of France's National Rally.

"A few months ago, Marine Le Pen was singing the praises of Austrian vice chancellor Heinz-Christian Strache, saying how formidable he was," French economy minister Bruno Le Maire said.

"(Strache) has been forced to resign. We find out why: that he was caught trying to sell his services to foreign forces. Behind this nationalist movement is a submission to foreign forces," Mr Le Maire told BFM TV.

German chancellor Angela Merkel said on Saturday: "We're having to deal with populist movements that in many areas are contemptuous of (European) values, who want to destroy the Europe of our values. We have to stand up to this decisively."

Austria's chancellor Sebastian Kurz, a conservative who formed a coalition with the Freedom Party in 2017, pulled the plug on his government and called for a snap election on Saturday after Mr Strache's resignation.

He met President Alexander Van der Bellen on Sunday to discuss the timetable for a new vote and the makeup of a caretaker government.

"This new beginning should take place quickly, as quickly as the provisions of the Federal Constitution permit, so I plead for elections ... in September, if possible at the beginning of September," the president said.

Voting is seen as impossible earlier because voters are away for the summer school holidays.

Europe's far-right parties have surged at the polls since 2015, when more than a million asylum seekers entered the European Union, mainly by foot across the Balkans.

Since then, far-right parties have become the dominant political movements in much of former Communist Eastern Europe and claimed a share of power in coalitions in Austria and Italy. Britain's 2016 vote to leave the EU altogether is seen as part of the same trend.

Neither Mr Salvini nor Ms Le Pen addressed the Austrian scandal directly.

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Mr Salvini and his allies hope to emerge as the fourth or even third largest bloc in the European parliament after this week's election, moving decisively into the mainstream.

"There are no extremists, racists or fascists in this square," Mr Salvini told Saturday's rally in front of Milan's Gothic cathedral.

"Here you won’t find the far right, but the politics of good sense. The extremists are those who have governed Europe for the past 20 years."

German television commentator Christian Nitsche said the Austrian scandal could have a wider impact by showing that the populist tide was not unstoppable.

"Austria can now send a signal that it is able to free itself from this whirlpool. This would probably not yet be a turning point on Europe's wrong path, but a sign of hope that a first country has the strength to turn away from baiting, anti-democratic politicians and parties," he wrote.

Istvan Ujhelyi, a Socialist member of the European parliament from Hungary, a country dominated by nationalist leader Viktor Orban's Fidesz Party, called Mr Strache "the first domino" in a line of likeminded politicians he predicted would soon be brought low.

"Next up are Salvini, Le Pen, Orban and the rest of the far-right puppets on the Moscow leash."