BRUSSELS (AP) — The last time federal elections were held in Belgium in 2019, it took nearly 18 months before a new prime minister could be sworn in to lead a seven-party coalition government.

The wait was even longer after the 2010 vote when the country needed 541 days to form a government, still a world record.

Belgian voters return to the national polls on Sunday, in conjunction with the European Union vote, amid a rise of both the far-right and the far-left in the country. The vote could mean complex negotiations ahead in a country of 11.5 million people who are divided by language and deep regional identities.

Belgium is split along linguistic lines, with francophone Wallonia in the south and Dutch-speaking Flanders in the north, and governments are invariably formed by coalitions made of parties from both regions.

The latest opinion polls suggest that a new headache is on the horizon.

Two Flemish nationalist parties are poised to gather the largest shares of votes in Flanders, with the far-right Vlaams Belang, which backs independence for Flanders, is expected to win more than 25% of the vote. Just behind, the right-wing nationalist New Flemish Alliance (N-VA) could get around 20% of the vote.

In French-speaking Wallonia, the Socialist Party is projected to garner as much as a quarter of the ballots ahead of liberals and the far-left Belgium’s Workers Party. Poorer Wallonia — whose decline started in the 1960’s while Flanders’ economy went up — traditionally leans in favor of national unity because the region would likely find it difficult to survive economically on its own.