ATLANTA (AP) — Officials in one of Georgia's most diverse counties are improperly rejecting absentee ballots cast in the state's nationally watched governor's race, voting rights groups said.

Three hundred ninety absentee ballots have been rejected in Gwinnett County — more than one-third of the total number of absentee ballots rejected across the state, The Atlanta Journal-Constitution reported .

Voting rights groups this week filed two separate lawsuits in U.S. District Court in Atlanta against Republican Secretary of State Brian Kemp and the Gwinnett County elections board, calling for the rejected ballots to be reviewed and reinstated if possible.

The most frequent reason Gwinnett County election officials rejected absentee ballots was for "insufficient oath information," including signatures, birth dates and addresses.

"The penalty for even the smallest clerical error or a question about the voter's signature is disenfranchisement, with no meaningful opportunity to cure any perceived discrepancy," the Coalition for Good Governance said in its lawsuit.

Kemp, who oversees elections, is the GOP gubernatorial nominee. His opponent, Democrat Stacey Abrams, would become the nation's first black female governor if she wins in November.

Gwinnett County elections board chairman Stephen Day, a Democrat, said the Atlanta-area county is following state law, not participating in some sort of "nefarious scheme."

In an email, he told the AJC it's possible that the county strictly follows the law, while other counties might use more "subjective judgment" when it comes to deciding whether to accept absentee ballots.

Kemp's office says that counties decide how to process absentee ballots and that they have opened an investigation to make sure counties are following the law.

More than 60 percent of residents in Gwinnett are non-white. Because of its large Latino population, it is the only county in the state that is required to provide elections materials in both English and Spanish.

Through Sunday, Gwinnett County had rejected about 8.5 percent of absentee ballots, the newspaper reported. Across Georgia, less than 2 percent had been rejected.

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Information from: The Atlanta Journal-Constitution, http://www.ajc.com

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