SPD SUFFERS

In Baden-Wuerttemberg in the southwest, the Greens for the first time became the strongest party in a state, with 31.1 percent of the vote, ZDF television projections indicated.

The state was a CDU stronghold for more than 50 years before turning to a Green-led coalition with the SPD in 2011 after the Fukushima nuclear disaster in Japan, and CDU support fell by another 12 percentage points on Sunday.

Also damaging for the CDU was the result in Rhineland-Palatinate, the home of former chancellor Helmut Kohl.

There, the CDU's Julia Kloeckner, who had positioned herself as a future candidate to succeed Merkel, failed to unseat SPD state premier Malu Dreyer.

It was the only bright spot for the SPD, the biggest loser overall. In Saxony-Anhalt, its support almost halved and in Baden-Wuerttemberg it sank by more than 10 percentage points.

Asked if the SPD's weak showing in those two states would trigger questions about SPD leader Sigmar Gabriel's future, deputy party chairman Ralf Stegner said: "No, not at all."

It is still unclear which coalitions will take power in each state, but the splintered vote opens the prospect of deep changes to the political landscape.