STOCKHOLM (AP) — Sweden is facing weeks of political uncertainty after the country's two rival blocs failed to secure a governing majority in elections that saw a boost for a far-right party amid growing discontent with large-scale immigration.

With most of the ballots counted, the governing center-left bloc has a razor-thin edge over the center-right opposition Alliance, with roughly 40 percent each.

Sunday's election saw the Sweden Democrats, an anti-immigrant party with roots in a neo-Nazi movement, win about 18 percent, up from the 13 percent it gained four years earlier.

The party, which has worked to moderate its image in past years, gained on a backlash against the challenges of integrating hundreds of thousands of immigrants that arrived in the Scandinavian nation of 10 million over the past years.