(CNN)German Chancellor Angela Merkel has ruled out setting an upper limit on refugees coming to Germany, defying her long-term coalition partner on an issue that threatens to open up a rift between the country's ruling political parties just two months before federal elections.
Merkel rules out limiting number of refugees in Germany
"On the issue of an upper limit, my position is clear," Merkel said in an interview broadcast live on Germany's ARD on Sunday. "I won't accept one."
Merkel will need the support of the Christian Social Union -- the more conservative sister party to Merkel's Christian Democratic Union -- in order to remain Chancellor after September elections.
On Monday, CSU leader Horst Seehofer reiterated his party's pledge to make the limit on refugees a reality.
"The cap is and remains a goal of the CSU," Seehofer said, although he refused to make the issue a red line in a coalition deal -- a softening of his previous stance.
In an interview in December, Horst Seehofer, head of the CSU, promised a cap of 200,000 refugees per year if his party is in a coalition government after the election.
It's the second public disagreement between the two parties in less than a month. Merkel abandoned her long-held position against same-sex marriage in June, opening the door for a vote on the issue in the German parliament, which passed just a few days later.
Some CSU politicians responded angrily. Hans Reichhart, member of the regional parliament in Bavaria, southern Germany, told Deutsche Welle that the CDU and CSU had made an agreement not to act on the issue during this parliament, which lasts until the election in September. "This agreement was broken," he said.
Carsten Koschmieder, political scientist at the Freie Universitat in Berlin, sees these spats as part of the parties' campaign strategy rather than signs of fundamental disagreement.
"We're seeing a good division of labor between the CDU and the CSU," he told CNN. While Merkel makes her appeals to more liberal voters, the CSU can take the more conservative position on these controversial issues and appeal to a different group of voters.