An international network that fights discrimination at soccer matches says a banner displayed at a weekend match between two Bosnian clubs was one of the worst examples of anti-gay expression it has seen this season, and urged authorities to punish whoever is responsible.

The giant banner stretched around one end of the Kosevo stadium in Sarajevo during a match between city rivals FK Sarajevo and FK Zeljeznicar on Saturday. It made reference to the International Day against Homophobia the following day.

The head of the Football Against Racism in Europe network, Piara Powar, on Tuesday urged authorities to punish whoever is responsible.

Bosnia, like most of the Balkans, is notoriously macho, and gays mostly hide their sexual orientation. This has started to change recently.