RALEIGH, N.C. — Three federal judges on Friday threw out the congressional voting maps the Republican-led General Assembly drew five years ago, ruling that two districts were gerrymandered along racial lines.

The ruling throws the March 15 primary into chaos, as the judges ordered state lawmakers to redraw the maps within two weeks and not to hold any elections for U.S. House until the maps are in place. A special session of the legislature would have to be called to approve new maps, and they might have to pass federal muster again.

Mail-in absentee voting started last week, and more than 8,000 ballots have already been requested, according to the State Board of Elections. It was unclear late Friday how many ballots have already been filled out and sent back in.

The three-judge panel ruled that the 1st Congressional District, which spreads like an octopus across northeast North Carolina and has a tentacle that dips into Durham County, and the 12th Congressional District, which snakes along Interstate 85 between Greensboro and Charlotte, were drawn specifically so that the majority of voters in each were black.

"There is strong evidence that race was the only nonnegotiable criterion and that traditional redistricting principles were subordinated to race," 4th U.S. Circuit Court of Appeals Judge Roger Gregory wrote for the court. "In fact, the overwhelming evidence in this case shows that a (black voting-age population) percentage floor, or a racial quota, was established in both CD 1 and CD 12. And, that floor could not be compromised."