(Reuters) - North Carolina Democrats filed a new legal challenge to partisan gerrymandering on Friday, asking a state court to order the redrawing before next year’s elections of congressional districts they say are designed to entrench Republican power.

The lawsuit accuses Republican state lawmakers of drawing unconstitutional voting district maps in the “most extreme and brazen partisan gerrymander in American history.”

In last year’s congressional elections, North Carolina Democrats won almost half of the votes, but netted only three of the state’s 13 seats in the House of Representatives.

“There is no dispute that the 2016 congressional map reflects an extreme and intentional effort to maximize Republican advantage,” the complaint said.

It was filed in court in Raleigh with the help of the National Redistricting Foundation, a non-profit group that fights gerrymandering, the practice of drawing voting maps to entrench one party’s power. The group is led by the prominent Democrat Eric Holder, who served as U.S. attorney general under former president Barack Obama.

Republican lawmakers in the state were open about their partisan intent when they redrew maps in 2016.

David Lewis, a Republican in the state’s House of Representatives in charge of the redistricting, told fellow lawmakers he proposed a map that gave a “partisan advantage” electing 10 Republicans and three Democrats only because he did “not believe it’s possible to draw a map with 11 Republicans and two Democrats.”

Earlier this month, a three-judge panel in the Raleigh court ruled that the state’s legislative map used for state-level elections was an illegal partisan gerrymander that must be redrawn. The lawsuit said that the congressional map, drawn in a similar way, “should now meet the same fate as the unconstitutional and invalidated state legislative maps.”

The state-level fight was the first to reach trial since the U.S. Supreme Court ruled in June that federal courts have no authority to curb partisan gerrymandering, though it did not prevent state courts from ruling on such cases.

The North Carolina Republican Party said in a statement that the lawsuit was an effort to tie up the state in “expensive legal shenanigans because they lost at the Supreme Court of the United States.”

“This isn’t about fair maps,” the statement said. “It’s about Democrats judge-shopping in order to subvert democracy.”

If Democrats win a majority in the currently Republican-controlled state legislature in the November 2020 elections, they would be in place to draw new congressional districts in 2021 after the decennial U.S. census is completed.