COLUMBUS, Ohio — Nearly 50,000 voters received incorrect absentee ballots in the county that is home to Ohio’s capital and largest city, elections officials said Friday as they promised corrected ballots would be mailed within 72 hours.

With about 240,000 ballots mailed, that meant one in five voters received a wrong ballot. The error happened Saturday afternoon when someone changed a setting on a machine that places absentee ballots into mailing envelopes, Franklin County elections officials said Thursday.

Some ballots had an incorrect congressional race, while others had the correct information but were sent to voters in a different precinct. The Franklin County Elections Board said 49,669 voters received incorrect ballots out of 237,498 that were mailed.

That represents 6% of Franklin County’s approximately 880,000 registered voters, and 0.6% of the 8 million voters registered statewide in the presidential battleground.

The process to print, stuff the replacement ballots in envelopes and mail them was underway Friday, the Franklin County Elections Board announced.

The board also said it will mail postcards to all affected voters detailing the situation and highlighting voters' options moving forward. Those options include voting in person at the board’s offices on the city’s north side.

The elections board said multiple checks are in place to ensure only one voter can cast a ballot, including rejecting any replacement ballots if someone went ahead and voted in person.

The news of the incorrect ballots brought renewed focus on an election seeing an unprecedented number of absentee ballot requests, spurred by the coronavirus pandemic and concerns about in-person voting.

On Tuesday, Ohio’s elections chief announced that Ohio’s 88 elections boards received a record number of absentee ballot applications. Republican Secretary of State Frank LaRose said 2,154,235 applications had been received — more than double the 1,091,188 absentee ballot applications at the same time four years ago.

LaRose said Friday that while the Franklin County board made “a serious mistake,” the county was working hard to fix it. LaRose noted Ohio’s elections boards are bipartisan to ensure fair elections.

“The bottom line is this: Ohioans can be assured — we will have a safe, secure, and accurate election,” LaRose said in a statement.

President Donald Trump, who has alleged fraud associated with voting by mail with no evidence such fraud exists, quickly cited the Franklin County case on Twitter, calling it a case of a “rigged election.”

No such evidence exists.

“Mr. President, it certainly was a serious mistake, but a serious mistake that we’re working hard to make right,” the board tweeted in response to Trump. “Our board is bipartisan and our elections are fair. And every vote will be counted.”

Just minutes after his tweet alleging fraud in Ohio, the president tweeted in support of Colorado, which has an all-mail balloting system.

“COLORADO! Your mail ballots are being sent out beginning TODAY! Fill them out and VOTE #TrumpPence2020!” the president tweeted.