A settlement was reached in a lawsuit filed on behalf of Sioux tribes that accuses South Dakota officials of ignoring a federal law that protects the voting rights of minorities.

The American Civil Liberties Union had sued the state for the Oglala and Rosebud Sioux tribes, claiming officials failed to secure federal approval for changes to election law in two counties that are home to Indian reservations.

A 1972 amendment to the Voters Rights Act requires that election law changes in certain areas must first be authorized by the Justice Department or the U.S. District Court in Washington, D.C.

The lawsuit alleged that about 600 election-related laws and regulations concerning Shannon and Todd counties were passed without federal approval, and that such authorization was sought fewer than 10 times.

Under the settlement, the state must obtain approval from the Justice Department on all voting law changes enacted since the amendment's adoption. It also suspends two statutes -- one concerning election runoffs and another city council seats -- that ACLU attorneys say put Indians at a disadvantage.

The population of Shannon County, home to the Oglala Tribe, is 94.2 percent Indian. Todd County, which encompasses the Rosebud Sioux Reservation, is 85.6 percent Indian.

The agreement must be approved by a three-judge panel in federal court.

The state elections supervisor said he felt the lawsuit was unnecessary because no one had ever voiced concerns about election laws before the suit was filed in August.