Angela Merkel's CDU 'seizes key state from rivals'
Germany's Christian Democrats (CDU) have unseated the Social Democrats in a key state election, exit polls say.
Chancellor Angela Merkel's CDU is projected to win 34.5% of votes in North Rhine-Westphalia, compared with 30.5% for the Social Democrats (SPD).
It was seen as a test for Mrs Merkel ahead of September's general election.
The SPD has run the state - Germany's most populous - for most of the post-war period. Party leader Martin Schulz said it was a "hard day".
Voters were choosing candidates for the state legislature, whose leadership may now change from its current SPD-Green coalition.
The SPD's vote is said to be down by 8.6 percentage points on the last election there in 2012, while the CDU vote is up by almost the same amount.
Mr Schulz had predicted a victory there would make him the next German chancellor - but the victory for Mrs Merkel's party will now give her a boost as she seeks a fourth term.
The first exit polls also predict 12% for the liberal Free Democratic Party (FDP); 6% for the Greens; 7.5% for the far-right Alternative for Germany (AFD); and 5% for The Left.
Schulz loses his shine - Damian McGuinness, BBC News, Berlin
"This is a hard day for social democracy," said Martin Schulz, visibly shaken. It is also difficult day for him personally. North Rhine-Westphalia is his home state and traditionally an SPD stronghold.
So although the concrete issues that shaped this election were primarily regional - such as schools, transport and security - this state also matters nationally. It is seen as a bellwether for national elections.
There was a boost in his poll ratings and a surge of excitement when Mr Schulz announced earlier this year that he would challenge Mrs Merkel - it became known as the "Schulz effect".
His plan was to win over voters with a down-to-earth approach. But policy proposals have remained vague, and critics say the folksy charm has started to wear thin.
Now that his party has lost three regional elections in a row, the polls are down and the Schulz effect may have vanished as quickly as it came.
The result could also mean the worst election result for the SPD since 1947, Die Welt newspaper reports.
Polls before the vote had suggested the CDU and SDP were neck-and-neck.
But the CDU's campaign - which targeted voters' frustration on issues such as traffic congestion, rising crime and education - appears to have swayed voters.
It promised to improve security, with longer prison terms for offenders and more funds for the police.