The two men competing to run as conservative candidate to become Germany's next chancellor have failed to resolve their week-long stand-off, sources said on Sunday, and their parties may now hold a vote to decide who stands.
Christian Democrat leader Armin Laschet and Bavaria's Markus Soeder were in constant contact, the sources said, while the Bild tabloid cited its sources saying chances of a compromise on Sunday in which one of the contenders withdraws had faded.
The leadership rift in Germany's ruling conservatives, which broke into the open a week ago, threatens to loosen their 16-year-old grip on power at an election this autumn where Angela Merkel will not seek re-election.
Laschet, the 60-year-old governor of North Rhine-Westphalia - Germany's most populous state - has staked a claim to succeed Merkel after recently being elected leader of the Christian Democratic Union.
Soeder, the 54-year-old chief minister of Bavaria and leader of the CDU's regional sister party the Christian Social Union, is more popular with voters and, sources say, commands majority support in their joint parliamentary caucus.
An ARD Deutschlandtrend survey on Friday found that 72% of conservative voters considered Soeder to better suited to become chancellor.
Bild reported on Sunday that work was going on behind the scenes to organise a leadership vote in the CDU/CSU faction, which meets on Monday to review a coronavirus protection bill and holds its regular weekly meeting on Tuesday.