NASHVILLE (AP) — Voter registration groups are asking a judge to block Tennessee's new restrictions for signing up voters from taking effect in October.

In a Nashville federal court filing Friday, the Lawyers' Committee for Civil Rights Under Law says the law has already curtailed registration efforts by the groups that sued: the NAACP state conference, the Equity Alliance, the Andrew Goodman Foundation and Democracy Nashville-Democratic Communities.

The new law is likely the first nationally to fine groups for too many incomplete registration forms. It includes misdemeanor charges for other intentional infractions of new rules. It says only paid groups could be penalized, though the legal filing contends the distinction is unclear.

Republican Secretary of State Tre Hargett has argued adding penalties bolsters election security. His office declined to comment on pending litigation.