German Chancellor Angela Merkel came under fresh fire over her open-door refugee policy Monday after her party suffered a humiliating defeat against an upstart anti-migrant populist party in her home state. The right-wing populist Alternative for Germany (AfD) party clinched almost 21 percent in its first bid for seats in the regional parliament of Mecklenburg-Western Pomerania on Sunday. With her eyes on national elections next year, AfD co-chief Beatrix von Storch hailed the shock outcome as "the beginning of the end of the Merkel era," while Bild daily labelled the result another "slap across the face" for the chancellor. The AfD's rise mirrors success enjoyed by other anti-immigration parties across Europe, with France's Front National (FN) riding high in the polls and a far-right populist eyeing the presidency in Austria in elections on October 2. Merkel's conservative Christian Democratic Union (CDU) won just 19 percent in its worst ever score in the ex-communist northeastern state, while the Social Democrats maintained top place with over 30 percent. The state vote was held exactly one year after Merkel opened German borders to a mass influx of Syrian refugees and other migrants that would swell arrivals in Europe's top economy to one million asylum seekers in 2015. While her welcoming stance initially won much praise, the mood has since considerably darkened as popular worries have grown about how to integrate the newcomers. The AfD has capitalized on such fears, especially since a spate of sexual assaults blamed on North African men on New Year's Eve, and a series of bloody attacks this summer, some claimed by the Islamic State group. With its latest win, the Islamophobic AfD, founded just over three years ago, is now represented in nine out of Germany's 16 regional parliaments, and hoping for more gains when the capital Berlin goes to the polls in two weeks. The state election in the sprawling farming and coastal state is the latest to serve as a bellwether ahead of national elections in late 2017. Merkel, in power for 11 years, has not yet said whether she will run for a fourth term but is widely expected to do so. Although Sunday's election was held in Germany's poorest and least populous state, the outcome was significant in part because it is home to Merkel's constituency, the port city of Stralsund. "This was more than a small state election, it was a vote on Merkel," said news site Spiegel Online, pointing at the "protest storm" in "Merkel's living room." The AfD's lead candidate in the state, Leif-Erik Holm, said "the icing on the cake is that we have left Merkel's CDU behind us." Carsten Brzeski of ING-DiBa bank wrote that the outcome was "another shot across the bow for the national government and Chancellor Angela Merkel." "The refugee crisis is damaging Chancellor Merkel's popularity, not only in the German population but also within the government coalition." Merkel's conservative Bavarian allies the CSU renewed their demands for tougher policies on migrants. The outcome was "a protest against the policies in Berlin," said its secretary general Andreas Scheuer, renewing calls for an upper limit to the refugee intake. The CDU's general secretary Peter Tauber acknowledged that Sunday's results were "bitter," acknowledging that voters "wanted to send a signal of protest." Merkel, who was attending a G20 summit in the Chinese city of Hangzhou, was due to discuss the outcome with her party in a teleconference on Monday.