"Thanks for the loophole," read one of the banners displayed by AIK supporters in their opening game of the season against BK Häcken.
The Swedish club's ultras have spotted a way to get around new anti-hooligan legislation banning face masks – by wearing niqabs.
Religious face coverings are exempt from the new law, which was passed in January and enacted in March under the guidance of Anders Ygeman, interior secretary in Sweden's government.
The AIK ultras' named Ygeman specifically in their display of gratitude for the loophole, and held aloft other messages, reading: "Freedom for ultras is the ultimate goal.
"AIK's ultras mean well. We're now wearing masks for religious reasons."
When Swedish law forbids masks/hiding faces in public places, but permits it for religious reasons... AIK fans adapt to conceal identities. pic.twitter.com/LcfRkFJXXV— Joel Rookwood (@Joelrookwood) April 4, 2017
Speaking to Swedish sports new outlet Sports Bladet, Ygeman said: "In all honesty I thought the banner was quite funny. It shows that AIK fans have a bit of humour.
"But I do not think we will see a "niqab trend" in the headlines this year."
AIK, who won the last of their five Allsvenskan league titles in 2009 and who finished runners-up in 2016, began the 2017 campaign with a 0-0 draw against Häcken.