Chancellor Angela Merkel's coalition has suffered a new blow as Germany's main opposition parties celebrated gains in a state election.
The latest setback came as Ms Merkel's unpopular government grapples with the eurozone debt crisis and other challenges.
The vote in Mecklenburg-Western Pomerania, a north-eastern region where Ms Merkel's parliamentary constituency is located, was the sixth of seven German state elections this year. Most of those have gone poorly for the chancellor's centre-right coalition.
The centre-left Social Democrats, who lead the state government but are in opposition nationally, won 35.7% of Sunday's vote - about five points more than five years ago, provisional official results showed.
The other winners were the opposition Greens, who have been riding high in national polls. They won 8.4%, entering the state legislature for the first time - which means they are now represented in all 16 German regional parliaments. National leader Cem Ozdemir called that "a true sensation".
Ms Merkel's conservative Christian Democratic Union, however, slid to 23.1% from nearly 29% in 2006, its worst showing yet in the state.
And its partner in the national government, the Free Democratic Party, slumped to just 2.7% - losing more than two-thirds of its support and its seats in the state legislature.
"The CDU is, of course, disappointed by this election result," senior MP Peter Altmaier told ARD television. He added that it pointed to the need "to stand together. ... This is the precondition for people to have confidence in our policies".
Over the coming weeks Ms Merkel faces the task of swinging sceptical centre-right politicians in Berlin behind the latest measures aimed at keeping debt-troubled eurozone countries afloat.
That adds to issues such as this year's abrupt decision to speed up Germany's exit from nuclear power, the country's abstention in a United Nations vote on the no-fly zone over Libya, and constant internal feuding over plans for tax cuts - all blamed for undermining centre-right support.