“There was so much that we had to evacuate a building in the western suburbs,” police spokesman Ulf Göranzon told Metro.
Three members of Svenska Motståndsrörelsen (‘Swedish Resistance Movement’ – SMR), men aged 18, 21 and 28, have been detained pending custody proceedings.
Police made six arrests in total following coordinated raids on the homes of SMR members and their parents.
The Nova Group, a police unit focused on counteracting the growth of organized crime, was involved in the swoop, which was carried out on Thursday.
Police have launched an investigation to ascertain whether the group intended putting the weapons to use.