Merkel 'heir' gives up on chancellor role: party source

The woman widely seen as German Chancellor Angela Merkel's chosen successor will not lead her crisis-racked CDU party into upcoming elections, a party source told AFP Monday.

Annegret Kramp-Karrenbauer, known as AKK, took over from Merkel as CDU chairwoman and presumed shoo-in for chancellor in 2018 but "has now said she will not be a candidate for the chancellery", the source said.

She made the surprise announcement after telling a crunch CDU meeting that the centre-right party had "an unresolved relationship" with the far-right AfD party and the far left.

It comes after an election debacle in the state of Thuringia in which regional CDU lawmakers went rogue and voted in the same camp as MPs from the AfD to oust a far-left state premier.

AKK "will by the summer organise the process to find the (chancellor) candidate, further prepare the party for the future and then give up the leadership", the source said.

The source added that Merkel wanted her to remain as defence minister, the post she has held since July.

Germany's next national elections must take place by autumn next year, although the fractious coalition between the CDU, its Bavarian CSU allies and the centre-left Social Democrats (SPD) may not hold until then.

The CDU has been in turmoil ever since the Thuringia fiasco, which broke a political taboo in Germany where mainstream parties have always ruled out cooperating with the AfD.

Merkel called the vote in Thuringia "unforgivable" and said the outcome "must be reversed".

While AKK rushed to the scene to try and convince CDU state lawmakers to back new elections, she left after hours of talks without bringing about a clear result, further calling into question her crumbling authority.