A federal appeals court panel ruled Wednesday that a Kansas law requiring proof of citizenship to register to vote is unconstitutional, upholding a judge's injunction that had banned its use.

A 10th Circuit Court of Appeals panel found in two consolidated appeals challenging the Kansas statute that the state law violates the Equal Protection Clause and the National Voter Registration Act.

The panel upheld the permanent injunction that U.S. District Judge Julie Robinson had imposed prohibiting enforcement of the requirement.