Berlin
(CNN)Partial results from Bavaria's state election Sunday show the ruling Christian Social Union is losing its majority in a humiliating performance that is likely to rattle German Chancellor Angela Merkel's fragile "grand coalition" government.
The Christian Social Union, or CSU -- the Bavarian sister party to Merkel's conservative Christian Democrat Union, or CDU -- has dominated politics in the state since the end of World War II, ruling for all but three years for nearly seven decades.
With 74 out of 91 voting districts counted, the CSU had garnered 38.8% of the vote, while fringe parties won a huge boost in the highly polarized vote.
That appears to be a big drop for CSU from the last election in Bavaria in 2013, when the party won 47.7% of the vote and took 101 of 180 seats.
Bavaria bore the brunt of the 2015 refugee crisis; at its peak, thousands of asylum seekers were crossing into the state every day. Since then, both Merkel and her CSU allies have been criticized for their management of the influx.
The pro-immigration, environmentalist Greens were running in second place with 15.8%, the early results show, increasing their support, while the far-right, anti-immigration Alternative for Deutschland, or AfD, party has taken 10.8% of the vote, giving it seats in parliament for the first time.
The early results generally reflect what was shown in exit polls. Official results were being slowly released as votes are counted, with full results expected early Monday morning.
The outcome is likely to have an impact on Merkel's coalition government, which took four months to form through difficult negotiations and has come close to imploding over migration issues and a scandal involving the country's spy chief.
The CDU has accused CSU members of pandering to far-right sentiments to prevent losing supporters to the anti-migrant AfD, in publicized infighting that has tarnished the image of the two parties.
German Chancellor Angela Merkel leads a fractured coalition.
The Social Democrats, known as SPD, also in Merkel's grand coalition, appear to have lost their second-place spot in Sunday's vote, winning 9.1% in the early vote count, around half of what they had in the 2013 election.
Speaking after exit polls had been released, SPD leader Andrea Nahles did not explicitly name Merkel but pointed to the Chancellor's coalition as a reason for her party's major setback Sunday.
"It would seem we were unable to convince the electorate, and that is bitter. Certainly, one of the reasons why we did not do well in the elections is the poor performance of the grand coalition here in Berlin," she said, adding that infighting had hurt all parties in government.
"One thing is sure: This needs to change."
Alice Weidel of the right-wing Alternative for Germany (AfD) speaking to supporters after exit poll results Sunday in Mamming, Germany.
Alice Weidel, the far-right AfD's parliamentary group co-leader, said the exit poll showed there was "no longer a grand coalition in Berlin."
"Those who have voted for AfD in Bavaria today also say Merkel must go, dear ladies and gentlemen," she said.
"Clear the path for new elections, clear the path for policy in our country."
Policy analyst Leopold Traugott from Open Europe told CNN that calls for a leadership change will grow louder from all three coalition parties: the CDU, CSU and SPD.
"The mood within Merkel's 'Grand Coalition' has been terrible for months now, and will be even worse following this election," he said.
"It is becoming increasingly clear to all parties involved that the current setup is not working in their favor."
Merkel, now serving her fourth term, could find herself fighting to keep her job as party chair when the CDU holds its annual congress in December. To ward off a mutiny in her coalition, she may be pressured to shake up her cabinet before the congress.
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'Lessons to be learned.'
Bavaria's State Premier Markus Soeder from the CSU said there were "lessons to be learned from Sunday's painful results," but as the frontrunner, the party still had the right to form government.
"Today is not an easy day for the CSU. We have not achieved a good result. We have achieved a painful result," he said.
"We accept this result with due humility and we will have to learn our lessons from it. We have to analyze it. One thing is for sure: Despite certain debates and comments and forecasts, the CSU is not only the strongest party, it has remit to form government, and that has to be said as well in this context."
Bavarian Governor Markus Soeder of the Christian Social Union (CSU) casting his vote in Nuremberg, Germany on Sunday.
If the trend in partial results continues, the center-right CSU could be left in the awkward position of trying to form a coalition with the left-wing Greens, having ruled out any kind of alliance with the AfD.
Bavaria appears to have followed electoral trends in other parts of Europe. Populist anti-migrant parties across the region have splintered traditional support bases on the left and right, leading to fractured election outcomes and more coalition governments.
CNN's Atika Shubert and Nadine Schmidt reported from Berlin. Angela Dewan reported from London and Karen Smith contributed from Atlanta.
