Belgium's far-right Flemish nationalist Vlaams Belang party made strong gains Sunday in national, regional and European elections, partial results showed.
The vote sets the stage for difficult negotiations to form a government, five months after the ruling coalition collapsed and left Prime Minister Charles Michel in charge of a caretaker administration with no majority.
With 40 percent of the votes counted in all three elections in the Dutch-speaking Flanders region, Vlaams Belang (Flemish Interest) was on course for 18 percent, around three times their score in the last elections in 2014.
The result would make Vlaams Belang -- which advocates the secession of Flanders from the rest of Belgium -- the second biggest party in the region, and joint second largest in Belgium's federal parliament, according to a projection by public broadcaster RTBF.
If confirmed by final results "this shows that Belgium is not spared by the result of extremist populism," Michel told RTBF.
In the European elections, Vlaams Belang, which is an ally of French far-right leader Marine Le Pen's National Rally, could end up with two MEPs.
- 'Virus of hate' -
The Vlaams Belang's advance came partly at the expense of the conservative nationalist N-VA, which looks set to drop five points to 27 percent.
The N-VA suffered after being in an uneasy coalition with Michel for four years but is set to remain the largest party in both the regional and federal parliaments.
"We have lost these elections, it's clear, but we remain the biggest party in Flanders. There are many losers but one big winner -- the VB. I congratulate them," N-VA chief and powerful Antwerp mayor Bart de Wever said.
Filip Dewinter, a leading figure in Vlaams Belang, signalled the party's desire to play a leading role in Flanders, saying the so-called "cordon sanitaire" erected by parties that refuse to deal with it because of its hardline politics "must be broken."
Socialist politician Ahmed Laaouej said Vlaams Belang had profited from the "anti-migrant rhetoric of the N-VA" during the 2015 migrant crisis, adding: "The N-VA has not stopped spreading the virus of hate."
French-speaking socialists meanwhile have the lead in Brussels, with 19 percent, and the francophone region of Wallonia, with 27 percent, according to an exit poll by the Free University of Brussels.
In Brussels the socialists may have to share power with the Greens -- reflecting broader gains for environmental politicians around Europe -- who doubled their score to 20 percent of the vote.
"Tonight the green wave is growing," said the Greens' Zakia Khattabi.
- 'Advance of the extremes' -
The socialists, long the main force in French-speaking Wallonia, also lost votes to the far-let Workers Party which is on course to get seven percent.
"The most striking outcome of this vote is the advance of the extremes," said Belgian Foreign Minister Didier Reynders, who is from Michel's Liberal party.
Voting in the triple election was also marked by a protest outside Brussels Gare du Nord station at which police said 200 "yellow vest" anti-establishment protesters were arrested.
The deepening Flanders-Wallonia rift will complicate any effort to agree a coalition in the 150-member federal all Belgium parliament that represents parties from both communities, underlining the rift in Belgium politics.
With 11 million people, Belgium is one of the EU's most divided member states. Dutch and French speakers choose separate candidates and parties. There is also a small German-speaking constituency.
This makes coalition building extremely complicated. Belgium took a record 541 days to form a government in 2010 and 2011 amid deep divisions between the Dutch speakers in Flanders and francophones in Wallonia and Brussels.
Making matters worse, economically booming Flanders votes traditionally to the right, while the socialists are the major political force in Brussels and post-industrial Wallonia, where unemployment is high.
The N-VA broke party tradition in 2014 and joined the coalition government with Michel, a French-speaking liberal, as prime minister.
The coalition collapsed in late 2018 when the N-VA jumped ship in opposition to Belgium's ratification of a United Nations migration pact.