COLOGNE, Germany (Reuters) - The anti-immigrant Alternative for Germany (AfD) looks set to turn further right after its co-leader, who has struck a more moderate tone of late, suffered a defeat when delegates refused to discuss her motion to shift the party into the "mainstream".
Support for the party, which attacks Chancellor Angela Merkel for having allowed more than a million migrants into Germany in the last two years, has tumbled in recent months after reaching the mid-teens in opinion polls last year.
Originally founded as an anti-euro party in 2013, the AfD is expected to enter the national parliament for the first time after September's election but is treated as a pariah by established political parties, which refuse to work with it. Its congress drew thousands of protesters to Cologne on Saturday.
Frauke Petry, the party's public face and under whose leadership the party has already shifted rightwards, shocked supporters on Wednesday by announcing she would not lead the AfD's campaign for a Sept. 24 federal election.
She had ruffled feathers internally by proposing that the AfD signal its willingness to join coalitions after elections in 2021 rather than entrenching itself as a "fundamental" force of opposition whose role is largely provocative. Her foes within the party say that division is artificial.
But delegates voted against discussing Petry's motion or another proposal in which she and others said the AfD should reject "racist, anti-Semitic ... and nationalist ideologies".
Instead, they stressed the need to show unity after months of bitter infighting that have helped drag down its poll ratings to less than 10 percent. Against her advice, they also voted to field a team of national candidates.
The AfD has been embroiled in a scandal since senior member Bjoern Hoecke called in January for a "180 degree turnaround" in the way Germany seeks to atone for Nazi crimes. Petry got two-thirds of the executive board to vote in February in favor of expelling him and a party arbitration body must now decide.
Delegates in Cologne declined to discuss ending attempts to oust Hoecke, in the only apparent setback to Petry's opponents.
Political scientist Hajo Funke said Petry had recently tried to steer the party on a more moderate course but had lost to more radical members like Hoecke and his supporters, leaving the door open to the AfD shifting further right.
"That means the direction now is that they want to integrate positions such as those held by Hoecke and that's a racial radical right-wing position," Funke said, adding that would make it less attractive to voters.
Petry said the AfD had made a "mistake" in refusing to discuss her motion on its future direction because it was "exactly this lack of strategy" that was behind much of its historic internal strife.
Addressing the congress, Petry's co-leader Joerg Meuthen was applauded for saying the AfD would never form an alliance with those like Merkel, Social Democrat leader Martin Schulz or the Greens, whose pro-migrant stances were wrecking Germany.
Up to 15,000 protesters demonstrated against the AfD's meeting in Cologne, a police spokesman said. Two police officers were injured and a police car was set ablaze.
In a fiery speech, economics professor Meuthen said Germans in his hometown were now "few and far between" and that without action, "the irrevocable change of our homeland into a Muslim-dominated country is a mathematical certainty".
He insisted he was not xenophobic but was concerned about how migrants were changing Germany. Many of those who have arrived in Germany in the last two years are Muslims.
He likened the country to the Titanic.
"Everybody is still in good spirits and there's a relaxed party mood above and below deck but it's almost impossible for the huge ship to make the necessary change in direction anymore," Meuthen said. "People can't or don't want to imagine a collision with an iceberg but it's already unavoidable."
Additional reporting by Andrea Shalal in Berlin; Editing by Catherine Evans