The challenges were among 35,000 that Republicans filed in 65 of Ohio's 88 counties Friday afternoon. They targeted newly registered voters whose mail was rejected as undeliverable.

The Hamilton County Board of Elections discovered Saturday some challenges had mismatched names and addresses, according to state GOP Chairman Bob Bennett. It was a clerical error when databases were merged, he said.

The party doesn't think there are problems with challenges elsewhere in the state, spokesman Jason Mauk said.

Hundreds of thousands of new voters have signed up this year, including 84,000 in Hamilton County alone. Some registrations collected by Democrat-affiliated groups are already being investigated as potentially fraudulent, and Republicans said they were issuing the challenges now to resolve eligibility before Election Day.

But Hamilton County Democratic Co-chairman Tim Burke said he doesn't think someone's right to vote can be challenged before they vote. "They were trying to hijack this election," Burke said.

Republicans will not resubmit the challenges, Mauk said, but they are encouraging the Board of Elections to internally review questionable registrations.

And Republicans have another shot at blocking voters they think ineligible, noted Chip Gerhardt, the county GOP official who delivered the challenges to the Board of Elections on Friday.

"There is still an option to observe and challenge on Election Day," he said.

County Republicans also submitted a list Friday of hundreds of people they intend to place in polling places as challengers on Election Day.

Democrats also named hundreds of challengers Friday but said that was only to keep an eye on Republicans, not to challenge voters.