Berlin (AFP) - German Chancellor Angela Merkel's hardline allies on Wednesday took aim at her backing for a new eurozone budget, opening up another front after an attack against her on immigration.
Merkel's Bavarian sister party CSU had on Monday already given her an ultimatum to curb migrant arrivals or risk pitching Germany into a political crisis that could rattle Europe.
But it now also takes issue with an agreement announced Tuesday by Merkel and French President Emmanuel Macron to set up a common budget for the eurozone which will fund investments in poorer member states.
"We were always very sceptical about a eurozone budget. Simply because it's a form of additional budget," Bavaria's state premier Markus Soeder told Sueddeutsche Zeitung.
"Is it separate from the German legislature? Does it mean that the fundamental stability of the euro will be challenged? All that must be clarified," said Soeder.
The CSU will call a coalition panel to examine the issue, he added.
Germans are deeply opposed to any "transfer union" that sees their taxes flowing to eurozone laggards.
Merkel herself had initially appeared lukewarm to the idea of a budget for the bloc.
But she has since offered a key concession in backing Macron's call for such a fund, even though she has said that the total sum should be in the low tens of billions range -- far less than what Paris had hoped for.
Neither Merkel nor Macron at a Tuesday summit mentioned a figure for the budget or how it would be funded, saying only that details would be determined by the eurozone's 19 members.
- Deep rift -
The CSU's attack on the eurozone reform proposal came in a week already marked by a deep rift between the Bavarian party and Merkel over her liberal refugee policy that allowed more than a million asylum seekers to enter Germany since 2015.
Merkel's decision has proven divisive, and voters in September's elections handed her her poorest score ever and gave seats for the first time to the far-right anti-Islam AfD.
Several high-profile crimes by migrants -- including a deadly 2016 Christmas market attack by a failed Tunisian asylum seeker -- have also fuelled public anger.
While Merkel won international accolades for her generosity towards migrants, she is now weaker than ever at home over her refugee policy.
She is now battling to save her coalition after Interior Minister Horst Seehofer of the CSU gave her a fortnight to find a European deal to curb new arrivals by a June 28-29 EU summit, failing which he vowed to order border police to turn back migrants.
If Seehofer makes good on his threat, Merkel could be forced to sack him, thereby triggering the collapse of her coalition.
- 'Don't mix finance and asylum' -
Coming to Merkel's rescue on the explosive issue, Macron on Tuesday said that Paris and Berlin had agreed to seek an EU deal to send back migrants registered elsewhere in the bloc.
Soeder, speaking in Linz after holding talks with Austria's Chancellor Sebastian Kurz, quickly claimed credit for the development.
"With Bavaria's clear position, Berlin would not have moved as quickly," he said.
At the same time, he warned Merkel against mixing European finance and asylum policies by offering European partners financial incentives in exchange for cooperation on migrants.
"They are two different areas. There must be a clear principle of the rule of law," he added in Linz on the Danube river.
Soeder's suggestion that Macron had backed Merkel in exchange for the eurozone budget was however firmly rejected by her spokesman Steffen Seibert.
Separately, the Social Democratic Party, the third party in Merkel's uneasy coalition, also spoke up in her defence.
"Soeder's daily sorties defy reality," SPD deputy chairman Thorsten Schaefer-Guembel told national news agency DPA, noting that the coalition had signed off on an investment budget for the eurozone in their negotiations three months ago.
"No one can help it if Mr Soeder was napping in the coalition negotiations," he said.