One of Angela Merkel's biggest allies has vowed to challenge her if she doesn't crack down on immigration

The head of Angela Merkel's biggest political ally has said his party would run against hers if she did not agree to a cap on migrants entering the country.Horst Seehofer, the head of the Bavarian Christian Social Union (CSU), said: "Without an annual threshold of 200,000 migrants allowed to enter Germany, the Christian Social Union will refuse to be part of the next government."According to Deutsche Welle, Seehofer told news agency DPA that if the chancellor did not agree to a cap being implemented for 2017, that the CSU would then run as an opposition party.Although Merkel, who is eyeing a fourth term as chancellor next year, has significantly toughened her stance toward refugees in the past few months, she has so far refused to agree to a cap.Merkel is determined to regain the support that she lost to the anti-immigrant party, Alternative fr Deutschland, and has signalled that she is prepared to go further than expected in her policies to counter the rise of populism.Earlier this month, she announced at her party's annual congress that she wanted to ban the full veil. On refugees, she added that "a situation like that of last summer cannot and should not repeat itself. This is my declared political goal."Seehofer said he was confident they would get the chancellor to change her mind on the cap, adding that it was an important measure that would allow Germany to keep taking in the people most in need.Though long-time allies (the CDU and CSU form the conservative faction in the Bundestag)the relationship between Merkel and Seehofer started eroding following the chancellor's handling of the refugee crisis. Seehofer was one of the loudest opponents to Merkel's welcome policy toward refugees.Bavaria was one of the counties in Germany most severely affected by the crisis as most of the hundreds of thousands of refugees entered the country through its southern border with Austria after going up the now-shut Balkan route from Greece.Seehofer drew criticism from Berlin when he visited Vladimir Putin in Moscow in February. He alsoinvited President-elect Donald Trump to visit Bavaria as soon as he was elected.Join the conversation about this storyNOW WATCH: The last time a losing candidate had a wider popular vote margin than Clinton was in 1876 ' here's the bizarre story
Click here to read full news..