LITTLE ROCK, Ark. — Cherokee Nation Entertainment on Friday filed a lawsuit challenging a constitutional amendment Arkansas voters approved this week that revokes its license for a planned casino in the state.

The lawsuit filed in federal court claims the measure approved by voters on Tuesday violates its constitutional rights, and seeks to block its enforcement before it takes effect Nov. 13. The constitutional amendment blocks a casino that was planned in Pope County.

Pope County was one of four sites where casinos were allowed to be built under a constitutional amendment that voters approved in 2018. Casinos have already been set up in the other three locations.

“Cherokee Nation Entertainment is firmly committed to protecting its constitutional rights, defending its lawfully issued casino license, and safeguarding the substantial investments it made in good faith based on the establishment of the Pope County casino license under Amendment 100 in 2018,” Bart Calhoun, an attorney for Cherokee Nation Entertainment, said in a statement.

The lawsuit is the latest in a costly fight between the Cherokee Nation and the Choctaw Nation of Oklahoma, which had spent at least $30 million combined on the campaign over the ballot measure. The state Supreme Court last month rejected a lawsuit by the Cherokee Nation that sought to disqualify the measure from the ballot. The Choctaw Nation operates a casino near the Arkansas border.

“This legal action to attempt to bypass the voice of Arkansas voters is not unexpected,” said Hans Stiritz, spokesman for Local Voters in Charge, the campaign backed by the Choctaw Nation in favor of the measure. “But we are fully confident in the process that brought Issue 2 to the ballot. Arkansas voters have spoken clearly on Issue 2 and we expect it to stand.”

Attorney General Tim Griffin called the lawsuit “baseless” and said he was prepared to vigorously defend the state.

The proposed amendment removes the Pope County casino’s authorization from the state constitution. It also requires future casino licenses to be approved by voters in the county where it would be located. The constitution currently requires casino license applicants to submit letters of support from local officials.

Cherokee Nation Entertainment has said it plans to build a 50,000-square-foot (4,600-square-meter) casino northeast of Russellville, 60 miles (97 kilometers) northwest of Little Rock. Plans also call for a 200-room hotel, a conference center and an outdoor music venue.