The head of Germany's Social Democrats (SPD) - part of the governing coalition - is to step down on health grounds.
Matthias Platzeck does not hold a seat in the German cabinet
Matthias Platzeck, 52, recently suffered a sudden hearing loss and spent several days in hospital undergoing tests.
He has been in office since taking over from Franz Muentefering in November, after coalition talks between the SPD and the Christian Democrats (CDU).
The CDU, led by Angela Merkel, narrowly won last year's elections.
The BBC's Ray Furlong in Berlin says Mr Platzeck's resignation is not expected to cause major problems for the government.
He says Mr Platzeck does not hold a seat in the cabinet but his departure can be seen as a sign of instability within the SPD, where some on the party's left feel he has been overshadowed by Chancellor Merkel.
The man reportedly nominated to replace Mr Platzeck is Kurt Beck, recently re-elected prime minister of the state government in Rhineland-Palatinate with a crushing majority.