BISMARCK (AP) — Two American Indian tribes have sued North Dakota, alleging the state’s new legislative map dilutes tribal members’ voting strength.

The federal lawsuit filed Monday by the Turtle Mountain Band of Chippewa and the Spirit Lake Tribe alleges violations of the Voting Rights Act.

North Dakota Secretary of State Al Jaeger, the state’s top election official, said Tuesday he had not seen the lawsuit and would not comment on it.

North Dakota’s Republican-controlled Legislature in November approved a new legislative map. It separates the state House districts on the Turtle Mountain Indian Reservation in northern North Dakota and the Fort Berthold reservation, in the heart of the state’s oil patch in the western part of the state and home to the Three Affiliated Tribes.

Some tribal members and lawmakers said the move would increase the odds for tribes to elect their own members to the Legislature.

Turtle Mountain argues the split House districts “packs” and “cracks” tribal members into a single house district on its reservation, while diluting their vote by non-native voters in the non-reservation subdistrict.

Spirit Lake alleges the new redistricting map dilutes American Indian voters on and near its reservation.

“Instead of creating fair boundaries as outlined in the Voting Rights Act, the map adopted by the North Dakota Legislature silences Native American voters on every issue, lowers the chance Native voters could elect a candidate they feel best represents their community, and prevents communities in these splintered districts from receiving a fair share of public resources,” Spirit Lake Tribe Chair Douglas Yankton Sr. said in a statement.