Merkel's Christian Democrats win in key German state election

German Chancellor Angela Merkel’s conservatives won a state election Sunday in their centre-left rivals’ traditional heartland.

The Social Democrats (SPD) conceded defeat in Sunday's vote in North Rhine-Westphalia (NRW), and their regional chairman, Hannelore Kraft, resigned.

"This is a great day for North Rhine-Westphalia," said local CDU leader Armin Laschet, who will most likely become state premier.

"We accomplished our two goals: defeating the SPD-Greens coalition and becoming the strongest party in the state."

Kraft said she took "personal responsibility for this defeat" before announcing her decision to step down.

The CDU won around 34%, up from 26.3% in 2012, according to an exit poll on public broadcaster ARD just after polls closed.

The western state of North Rhine-Westphalia is Germany’s most populous and has been led by the center-left Social Democrats for all but five years since 1966.

Martin Schulz said the poll in the state, Germany’s most populous and regarded as a centre-left stronghold, represented “a difficult day for the Social Democrats (SDP), a difficult day for me personally as well. I come from the state in which we took a really stinging defeat today.”

The results mean the SDP-Green coalition is unlikely to hold a majority in the state legislature and puts the CDU in position to replace it.

 “The CDU has won the heartland of the Social Democrats,” said the Christian Democrats’ general secretary, Peter Tauber, calling it a great day.

“This is a really bitter day for the Social Democrats,” said his Social Democratic counterpart, Katarina Barley. But she added: “The national election campaign is only beginning now.”