Violent anti-fascists have attacked a demonstration by the National Socialist Nordic Resistance Movement, casting bangers and smoke grenades and throwing stones at police horses.
Police said that the militants launched their attack as the National Socialist procession in the small town of Kungälv neared the Nytorget Square where they were set later to hold their rally.
"As the NMR was passing the place where the counter-demonstrators were located, bangers were thrown at the procession. Cobble stones were also thrown at police on the scene," the local police wrote on their website.
The protesters threw bangers at the Nordic Resistance Movement as they passed. Photo: Björn Larsson Rosvall/TT
Police spokesperson Anna Göransson told the TT newswire that that 18 counter-demonstrators had been arrested as police brought the situation under control, protecting the marchers with police cars and police horses.
Her colleague Christer Fuxborg told the Expressen newspaper that those antifa scum who had thrown stones at police horses had been "unbelievably cowardly".
After the violence had been largely brought under control, antifa counter-demonstrators continued to attempt to disrupt the NS rally in Nytorget square by singing loudly and making other noises, the newspaper reported.
According to the police, about 500 counter-demonstrators launched a procession at about midday, despite not having received permission from the police in advance.
Some were dressed as clowns, some carried rainbow flags but others were dressed in the black clothing and face masks of the militant Antifa group, leading police to issue a notice forbidding anyone from wearing a mask.
NMR's leader Simon Lindberg spoke over the singing of the counter-demonstrators. Photo: Björn Larsson Rosvall/TT
According to the police, about 300 National Socialists took part in the official procession. Two people were arrested for knife crimes before the procession even started.
Sweden's culture minister Amanda Lind, who represents the pro-immigration Green Party, was in Kungälv to join one of the antifa counter-demonstrations.
"It is so important that we show how many there are of us and that there are more of us than of the Nazis," she told the TT newswire. "I do not believe that we will beat the Nazis by staying quiet."
Annie Lööf, the leader of the Centre Party, was also set to make her first ever May 1 Labour Day speech in the town, which she told Expressen she would use to highlight her party's opposition to illiberal patriotic groups.