Germany's center-left Social Democratic Party (SDP) won Sunday's general election with 25.7 percent of the vote, beating the conservative union CDU/CSU, according to the provisional election results released by the Federal Returning Officer early Monday morning. 

The SDP's share of the vote surged by 5.2 percentage points from four years ago, while its main rival the conservative union of Christian Democratic Union (CDU) and its sister party Christian Social Union (CSU) suffered heavy losses. 

The provisional results showed the CDU/CSU union took only 24.1 percent of the vote in this year's parliamentary election, 8.9 percentage points lower than in the last election.