The reports comes after police broke up a march by neo-Nazi group Nordic Resistance Movement (Nordiska motståndsrörelsen, NMR) in Gothenburg on Saturday.
“We have concluded that there is a picture which threatens police, whereby Nordfront, on its website, asks for the names and addresses of police officers whom they filmed on Saturday,” police spokesperson with the Västra Götaland district Ulla Brehm told broadcaster SVT.
“Since we urge the public to report threats, we are now doing that ourselves. But I cannot go into further detail,” Brehm added.
On Saturday, around 40 NMR supporters demonstrated in Gothenburg without police permission. 16 people were arrested as a result.
In September this year, a major NMR march in the city – which had been allowed to go ahead by authorities – required heavy police presence and ended in a number of arrests.
After that march, a spokesperson for the group suggested future marches would be carried out without permission.