Witnesses say up to 100 men in masks marched through the center of Stockholm on Friday, assaulting anyone who appeared to be an immigrant, the Local reports. While police aren't confirming any attacks on migrants, they do say the men were passing out flyers meant to incite attacks, according to the BBC. And the Guardian quotes a police spokesperson, who says the men gathered "with the purpose of attacking refugee children." The Local reports the flyers warned that "the North African street children who are roaming around" will get the "punishment they deserve."
The violence appears to be in response to the murder of a young social worker at a center for migrant youths earlier this week, the Local reports. Police say "hooligan gangs for Stockholm football teams" and "far-right groups" are believed to be behind it. A Swedish neo-Nazi group issued a statement claiming responsibility and boasting that it had cleaned up the streets. According to the Guardian, a handful of people were arrested—one for allegedly assaulting a police officer, the others on suspicion of wearing masks in public, causing a disturbance, or possessing knuckledusters—and later released.