Germany's Social Democrats narrowly won Sunday's national election, projected results showed, and claimed a "clear mandate" to lead a government for the first time since 2005 and to end 16 years of conservative-led rule under Angela Merkel.

Germany's center-left Social Democrats (SDP) finished with 25.7% of the vote, beating Chancellor Angela Merkel's CDU/CSU conservative bloc, who came in at 24.1%, official figures on the website of the country's election commission showed Monday.

The preliminary results are based on ballots counted in all constituencies. The result is the worst yet for Merkel's CDU-CSU bloc. The Green party placed third at 14.8%, followed by the liberal FDP at 11.5%. The far-right Alternative for Germany garnered 10.3%.