Sweden's Prime Minister Stefan Löfven | Erik Simander/AFP via Getty Images Stand up against white supremacists, says Sweden’s PM Stefan Löfven decries ‘angry men with big words, small hearts and closed fists.’

Swedish Prime Minister Stefan Löfven warned Sunday against the rise of neo-Nazis and white power movements, saying people should not start "tolerating the unacceptable."

"It may be easy to try to laugh away these angry men with big words, small hearts and closed fists," he said in a speech in Eskilstuna, citing recent rallies by “Nazi groups, the Ku Klux Klan and white power protesters in Charlottesville,” Bloomberg reported.

"But all fascist movements were small when they were founded and were able to quickly gain followers during difficult times."

Löfven’s Social Democratic Party will face the far-right Sweden Democrats, which has roots in the white supremacist movement, in the election in 2018. Mainstream Swedish parties have consistently refused to cooperate with the Sweden Democrats, a position Löfven reiterated on Sunday.

In Berlin on Saturday, more than 500 neo-Nazis tried to march to the place where Rudolf Hess died 30 years ago, but were stopped by an estimated 1,000 counterprotesters, AP reported.

Swedish neo-Nazi group the Nordic Resistance Movement regularly made headlines earlier this year when openly demonstrating at various political events.