VIENNA — Sebastian Kurz, Austria’s 31-year-old foreign minister, declared victory for his center-right party Sunday in a national election that set him up to become Europe’s youngest leader and put the country on course for a rightward turn.
The Interior Ministry said nearly completed final returns showed Kurz’s People’s Party in first place with 31.4 percent of the vote, a gain of more than 7 percentage points from the 2013 election. Kurz described the jump in support as the biggest in party history.
The right-wing Freedom Party came in second, with 27.4 percent of the vote. The center-left Social Democratic Party of Austria, which now governs in a coalition with the People’s Party, got 26.7 percent.
Both the People’s and Freedom Parties campaigned on introducing tough measures to curb immigration and to pressure foreigners already in the country to integrate. The two parties are expected to form the next government coalition.
Noting that his center-right party had triumphed over the rival Social Democrats only twice since the end of World War II, Kurz called it a ‘‘historic victory.’’
‘‘Today is not the day of triumph over others, but today is our chance for real change in this country,’’ he told cheering supporters.
Still to be counted are more than 800,000 absentee ballots and ones cast by voters outside of their home districts. The outstanding votes are due to be tallied by midweek.
However, the votes counted so far show that Austria, where moderate policies have been the norm for decades, will have a government with a harder line on migration and Muslims than the one running the country now.
Both Kurz’s party and the Freedom Party — Kurz’s most likely government coalition partner — campaigned on the need for tougher immigration controls, quickly deporting asylum-seekers whose requests are denied, and cracking down on radical Islam.
Interior Minister Wolfgang Sobotka said the People’s Party received 31.4 percent of the vote, a gain of more than 7 percentage points from the 2013 election. Kurz described that as the biggest jump in support in the party’s history.
The election returns suggest a harder line on immigration resonated with voters more strongly than Social Democratic calls for social equality. Christian Kern, the Social Democratic chancellor, acknowledged as much, saying Sunday’s results reflected ‘‘a push to the right.’’
The Social Democrats were also hurt by charges of dirty campaigning after Israeli political adviser Tal Silberstein, while under contract to the party, launched Facebook platforms crudely mocking Kurz and suggesting the young foreign minister was anti-Semitic.
Much of the People’s Party’s appeal has been credited to Kurz. Since taking the helm in the spring amid growing strains within the governing Social Democratic-People’s Party coalition, he moved his center-right party further to the right.
Even though he is part of the present government, Kurz also presented himself as an engine of change for voters disenchanted with the political status quo.
But he avoids the inflammatory rhetoric of the Freedom Party and its head, Heinz-Christian Strache.
That made Kurz’s party appealing to voters who were uncomfortable with the Freedom Party, but increasingly concerned about immigration since 2015, when hundreds of thousands of mostly Muslim migrants flowed into and through Austria.
Kurz’s political career started eight years ago when the law student was elected chairman of his party’s youth branch.
Smart and articulate, he eventually caught the eye of People’s Party elders. He was appointed state secretary for integration, overseeing government efforts to make immigrants into Austrians, in 2011.
After a Social Democratic-People’s Party coalition was formed four years ago, Kurz, then 27, became Austria’s foreign minister — the youngest top diplomat in Europe.