RALEIGH, (AP) — The North Carolina Supreme Court has upheld the boundary lines for General Assembly and congressional districts drawn by Republicans three years ago that helped the GOP strengthen its grip on legislative seats.

A majority on the state's highest court ruled Friday that a three-judge panel was correct last year to determine the lines were lawful under the state and federal constitutions. Two justices disagreed.

The Republican-led state legislature approved the maps in 2011. U.S. Justice Department attorneys signed off on the maps, but election and civil rights advocacy groups and Democratic voters sued, arguing the boundaries are racial gerrymanders that cluster black voters in districts to benefit Republicans.

GOP leaders and their lawyers called the districts lawful and designed to protect the state from legal claims under the Voting Rights Act.