The Swiss federal government has confirmed a dominant performance in legislative elections by a nationalist party that seized on widespread concerns about mass migration in Europe, marking a shift to the political right.

Official results released Monday showed that the anti-immigration Swiss People's Party collected 29.4 percent of the vote, an increase of nearly 3 percentage points from the previous election to the lower house of parliament, the National Council, in 2011.

The Social Democrats were a distant second, virtually unchanged at 18.8 percent. The pro-business Free Democrats increased by 1.3 percentage points to 16.4 percent.

Turnout was 48.4 percent. Analysts cited voter fatigue for that relatively low figure.

The result was likely to weigh heavily on National Council voting for the seven-member executive Federal Council on Dec. 9.