Germany's interior minister Horst Seehofer will resign both his office and his position as head of the hardline conservative Bavarian CSU party after a weeks-long migration battle with Chancellor Angela Merkel, party sources said.
Mr Seehofer and his party spent hours finding a response to a hard-fought agreement to reduce migration into the European Union and so-called "secondary migration" between member states hammered out by Ms Merkel at a leaders' summit last week.
Now "he wants to step down as party chairman and interior minister" as he enjoys "no support", the sources said.
The CSU had pressured Ms Merkel for weeks to either agree to its plan to turn away at the border asylum seekers already registered in other countries or to achieve EU deals that would have the same effect, setting her a deadline of today.
Sources said Mr Seehofer complained in today's closed meeting with party bosses that he had endured a "conversation with no effect" with the chancellor yesterday about whether the EU-wide deal and string of bilateral agreements she struck met his demands.
Meanwhile, the general secretary of Ms Merkel's CDU party Annegret Kramp-Karrenbauer said in Berlin the chancellor's camp was "united" behind "effective, humane solutions together with our European partners".
It was not immediately clear whether the CSU would seek to remain in coalition with the CDU and offer a replacement for Mr Seehofer.
Alternatively it could break up the two parties' decades-long alliance, effectively depriving Ms Merkel of her majority in parliament and pitching Germany into uncharted political waters.