COLUMBIA, S.C. (AP) — The biological mother of a girl at the center of a South Carolina adoption dispute has sued the federal government, saying a law governing the placement of Indian children is unconstitutional.

In her lawsuit, filed Wednesday in federal court in South Carolina, Christy Maldonado asks U.S. Attorney General Eric Holder for a declaration that parts of the Indian Child Welfare Act are illegal. Those measures — which include a preference for "other Indian families" over prospective non-Indian adoptive parents — should be nixed because the law uses race in determining with whom a child should live and therefore violates equal protection provisions, Maldonado argues.

The act was passed in 1978 to reduce the number of Indian children being removed from their homes by public and private agencies and placed with non-Indian families. The law, Maldonado said in the lawsuit, was enacted with good intentions but ended up "sweeping within it children who do not have, and would not have — but for ICWA — any connection whatsoever to any Tribe other than biology ... and irrespective of whether their sole custodial birth mothers — their only legal parents — have even a trace of Indian blood."

Maldonado, who is Hispanic, was unmarried when she got pregnant and worked closely with a non-Indian couple hopeful of adopting her daughter. Her lawsuit includes 10 unnamed plaintiffs who are also unmarried mothers of children of Indian heritage who, because of the federal law, fear the adoptions of their children won't be finalized because the prospective parents are non-Indians, according to court documents.

Maldonado's lawsuit also names the Cherokee Nation as a defendant. Spokeswomen for both the nation and the federal government did not immediately comment on the lawsuit.

A Charleston-area couple has been trying to adopt Maldonado's now-3-year-old daughter since the girl's birth. Veronica lived with Matt and Melanie Capobianco for the first two years of her life but has been with her biological father since 2011, when the South Carolina Supreme Court ruled that, because of the federal law, Dusten Brown should have preference because of his Cherokee heritage.

The Capobiancos appealed that decision to the U.S. Supreme Court, which ruled this year that federal law did not actually require that Veronica — who is about 2 percent Cherokee — be given back to her Cherokee father.

But the ruling didn't directly award the girl to the Capobiancos, instead leaving it to South Carolina courts to decide where Veronica should end up. Last week, the state Supreme Court ordered a family court to finalize the Capobiancos' adoption of the girl, a decision that court upheld Wednesday.

No formal transition timetable has been set. Brown is also pursuing custody of her in Oklahoma, and his parents also are seeking guardianship through the Cherokee court system. Several American Indian groups have said they plan to file their own federal lawsuit to protect Veronica's interests.