Angela Merkel's would-be successor as German chancellor has threatened to stand down as leader of the CDU if her centre-right party fails to back her.
Annegret Kramp-Karrenbauer acknowledges the applause after a defiant speech at her party's annual congress in Leipzig. Photo: AFP
Annegret Kramp-Karrenbauer, known as AKK, urged critics to support her vision for Germany at the party's annual congress in Leipzig.
She has faced mounting criticism since replacing Mrs Merkel as CDU leader.
However, her threat to resign prompted a lengthy ovation and a pledge of loyalty from her main critic.
Poor election results and her low popularity have led to discontent within the CDU. But in a speech on Friday, Ms Kramp-Karrenbauer, 57, issued an ultimatum to her opponents.
"If you are of the opinion that the Germany I want is not the one you want... then let's end it. Here, now and today," Ms Kramp-Karrenbauer told delegates.
"But, dear friends, if you want this Germany, if you want to take this path together... then let's roll up our sleeves here and now and make a start."
At the end of the speech, delegates gave the party leader a standing ovation that lasted at least three minutes.
Mrs Merkel, who also gave a speech at the congress, struck a more conciliatory tone, calling for party unity.
Annegret Kramp-Karrenbauer, left, and Angela Merkel compare notes at the party congress. Photo: AFP
As leader of the Christian Democratic Union - Germany's largest party - Ms Kramp-Karrenbauer is favourite to succeed Mrs Merkel when she stands down in 2021.
She was also given the role of defence minister during the summer, but shocked colleagues when she suggested sending German soldiers to northern Syria as part of a an international security zone.
Friedrich Merz, a millionaire lawyer who narrowly lost out to Ms Kramp-Karrenbauer in last year's leadership vote, recently described the CDU-led government as "abysmal".
He remains one of Ms Kramp-Karrenbauer's most vociferous critics but applauded her speech and promised loyalty. "We are loyal, to our chairwoman, and to the government," he said.
Mrs Merkel has been chancellor since 2005 but with her fourth consecutive term due to end in December 2021, party turmoil has thrown AKK's candidacy into doubt.
Earlier this year, she was forced to dismiss a report that she believed Ms Kramp-Karrenbauer was not up to the job.
Since then, a fractious debate about the political direction of the party has escalated.
In the European Parliament elections in May, the conservative bloc had its worse result since World War II. The CDU and its sister party, the Christian Social Union, finished on top but support fell to 28.9 percent - down more than 7 percent from the last election four years ago.
Then, in October, the far-right Alternative for Germany (AfD) beat the CDU into third place in the eastern German state of Thuringia.
Who is AKK?
Popular in Berlin and her home state of Saarland in the south-west, Annegret Kramp-Karrenbauer has a reputation for calm analysis and political acumen.
She joined the party as a student in 1981 and quickly rose up the ranks of state politics, becoming the first woman to serve as a state minister for internal affairs in 2000, and the first woman to serve as prime minister of Saarland.
A Merkel loyalist, she is expected to replicate much of the chancellor's style and policy.
She has differentiated herself from her mentor, however, by voting in favour of quotas for women on corporate boards and by taking a tougher line on Russia.
She is also more conservative on social issues like gay marriage, and has vowed to review the country's position on security and migration.
- BBC