German conservative leader Armin Laschet is facing mounting unrest within his party, after their historic defeat in federal elections.
As he and the other party leaders met colleagues to decide their next steps, support for his bid to form a coalition drained away.
Bavarian Premier Markus Söder offered little hope when he said the centre left had the best chance.
Election winner Olaf Scholz will need the support of two other parties.
The Social Democrat leader called for urgent talks with the Greens and liberals, but their leaders planned to meet each other first.
Mr Scholz has been buoyed by opinion polls that suggest widespread backing for a three-way government.
