Angela Merkel 'to step down' as leader of Germany's ruling party

German chancellor Angela Merkel will give up her party leadership after 18 years, sources say, in a surprise move that points to her waning power.

Merkel has led the Christian Democratic Union (CDU) for 18 years and has been leader of Germany since being elected in 2005. German media is reporting that she will stay on as head of government for the time being, but will not seek re-election as party leader in December.