Voters in Germany's Berlin region have given Chancellor Angela Merkel's ruling coalition partners a sound defeat in a regional election.

Preliminary results on Sunday gave Ms. Merkel's conservative Christian Democrats 23 percent of the vote for the local legislature, behind the left-leaning Social Democrats, who had 29 percent. The Greens had 18 percent.

Ms. Merkel's coalition partners, the Free Democrats, won an embarrassing 2 percent of the vote, failing to qualify for any seats in Berlin. Free Democrat leader Christian Lindner said it is time for humility and refection on how to make the party more attractive.

Sunday's biggest surprise was the strong 9 percent won by the newly formed Pirate Party, whose members advocate more privacy and copyright protection for the Internet.

The Merkel coalition also was trounced in the last two regional elections — the latest just two weeks ago in Mecklenburg-Western Pomerania.

Ms. Merkel is halfway through a four-year term. Her coalition's election setbacks could weaken her hand as she faces a crucial vote in parliament on euro zone measures at the end of the month.