A coalition of civil rights groups is challenging a Georgia law that doesn't allow new voters to register before a closely watched runoff election in the 6th Congressional District.
The Washington, D.C.-based Lawyers' Committee for Civil Rights Under the Law filed a federal lawsuit Thursday in Atlanta on behalf of the groups.
The registration deadline was March 20.
Anyone not registered by that date can't vote in the June 20 runoff between Democrat Jon Ossoff and Republican Karen Handel, the top two vote-getters in Tuesday's 18-candidate election.
The lawsuit says that violates federal law.
Secretary of State Brian Kemp's spokeswoman called the suit "politically motivated."
Candice Broce says a runoff is a continuation of an initial election under Georgia law. She says last-minute changes would complicate preparations for the runoff.