A U.S. judge on Monday blocked a Louisiana Republican redistricting map that created only one majority-Black congressional district in the state, ordering the state legislature to redraw the map with a second such district within the next two weeks.

District Judge Shelly Dick found the Republican map likely violated the U.S. Voting Rights Act of 1965, a landmark piece of civil rights legislation, and issued an injunction against it.

"The appropriate remedy in this context is a remedial congressional redistricting plan that includes an additional majority-Black congressional district," the judge wrote.

Louisiana Republicans immediately appealed the ruling.

Similar battles are taking place in other states as Republicans and Democrats each attempt to draw maps favorable to their chances under the redistricting that takes place every 10 years.

At stake is control of the U.S. House of Representatives in November's midterm elections.

In Louisiana, where Democrats hold only one of the six congressional seats and African Americans account for one-third of the population, a second Black district could add another seat to the Democratic column. Blacks overwhelmingly vote Democratic.

Elsewhere, Republicans have achieved favorable maps in states including Florida, Georgia and Texas.

In New York state, Democrats tried to draw a map that would tilt even more in their favor, but were overruled by the state's top court. Instead a more competitive plan was approved.

Should any state challenge reach the U.S. Supreme Court, the favor could lean toward the Republicans.

In February, the increasingly assertive conservative majority on the Supreme Court allowed Alabama to move forward with a contested map that was favored by Republicans, granting an emergency request to put on hold a lower court's injunctions ordering that the map be redrawn because it likely discriminates against Black voters. The top court said it would take up and decide the Alabama dispute on the merits.

That decision signaled a potential further weakening of the Voting Rights Act, which has been used to counter racially biased voting and redistricting practices.