A group of Ainu, an ethnic minority in northern Japan, filed a lawsuit Monday against authorities to grant them an exemption from a ban on the commercial fishing of salmon in rivers.

While the law stipulates that the Ainu are an indigenous people, it does not guarantee their self-determination and other tribal rights, with the government citing there are no Ainu tribes.

The suit, filed with the Sapporo District Court against the central and Hokkaido governments, is the first such lawsuit by Ainu people to confirm their indigenous rights.