Finland's junior coalition partner, the Finns party, has chosen a strident nationalist - anti-immigrant and anti-EU - as party leader. The selection will test the bonds of the governing coalition.
Hardliner Jussi Halla-aho won 56 percent of votes at a Finns party congress on Saturday, while his more moderate opponent, Sampo Terho, won just 37 percent.
Halla-aho serves as a member of the European Parliament, but nonetheless advocates Finland leaving the EU. He has recently urged tighter immigration controls in Finland, and threatened to abandon the three-party governing coalition.
"We must be more aggressive in raising the topics that distinguish us from other parties... it is important to push our priorities forward more vigorously within the government program," Halla-aho told reporters after the vote.
The populist party has a troubled past - it was fined by Finland's Supreme Court in 2012 for comments on a blog that linked Islam to pedophilia and Somalis to theft. It joined the ruling coalition with centrist partners in 2015. It has drawn international attention by complicating EU bailout talks during the Eurozone crisis,
Prime Minister Juha Sipila has not yet commented on the government's future, but is due to meet Halla-aho on Monday.
As snap elections are very rare in the Scandinavian country, a possible break-up of the coalition would likely mean that Sipila's Centre Party would try to form a new coalition from the current parliament.
Government reforms imperiled
Political turmoil could upset healthcare and local government reforms at the heart of Sipila's plan to balance public finances.
"This (leader change) requires serious consideration. The Finns party is not the same party anymore," Finance Minister Petteri Orpo told Verkkouutiset, an online news site close to his National Coalition Party (NCP), but did not comment further.
He, too, is expected to meet Monday with Sipila and Halla-aho.
New Finns Party chairman Jussi Halla-aho (center) is congratulated by his rivals, Sampo Terho (right) and Lena Meri
Afterbecoming the second-biggest party in parliament, the Finns softened its nationalist and anti-EU stance. However, they have also seen their support plunge from 17.7 percent in a 2015 election to about 9 percent in the latest poll.
Mari K Niemi, a researcher at University of Turku, said the government may break up due to the change.
"The image costs to NCP for cooperating with the Finns party led by Halla-aho may be quite considerable," he said. "NCP joined the coalition with a populist party that partly sought to represent underprivileged people in the rural side. That party is now becoming a more radical right-wing populist party with a focus on criticizing immigration."
Finland is recovering from a decade of stagnation and economic problems including the decline of Nokia's former phone business. The government has sought to increase growth and rein in public debt by reducing spending and reforming labor laws.
bik/rc (Reuters, AP, AFP, dpa)