Two days after the Koi Nation Native American tribe announced plans to build a $600 million casino and resort in Santa Rosa, the Federated Indians of Graton Rancheria, who run the largest gaming operation in the area, said they opposed the move and cast doubt on the Koi Nation’s historical ties to the area.

“This is an egregious attempt at reservation shopping outside the Koi Nation’s traditional territory and within the territory of other federally recognized tribes,” said Greg Sarris, the chairman of the Federated Indians of Graton Rancheria, which operates the Graton Resort and Casino in Rohnert Park, in a statement.