Ohio, the first state to cancel its in-person voting in favor of an entirely mail-in election, has hit some hiccups as the state tries to transition voting procedures amid the COVID-19 pandemic.

Republican Secretary of State Frank LaRose, the state’s chief election official, wrote in a letter to Ohio’s Congressional delegation that due to delays with the United States Postal Service, some voters likely will not receive their requested absentee ballots in time for the Tuesday night deadline to return them.

“As we approach the April 28th deadline to complete the election, we are faced with an obstacle that is outside of our control, and we need your help to overcome it. As Ohioans rush to submit their vote-by-mail requests, and our boards work overtime to fulfill them, we are finding that the delivery of the mail is taking far longer than what is published by the United States Postal Service (USPS) as expected delivery times,” LaRose wrote in his letter.

“As you can imagine, these delays mean it is very possible that many Ohioans who have requested a ballot may not receive it in time,” he continued.

On Friday afternoon, LaRose announced that the USPS is putting in place extra provisions to ensure ballots are processed, including hand-delivery for some ballots.

At the beginning of April, voters in Wisconsin were asked to head to the polls after the Republican-controlled legislature and conservative courts blocked efforts from Democratic Gov. Tony Evers to expand absentee voting in light of coronavirus.

Now, even after a statewide effort from both Republicans and Democrats, officials in Ohio are preparing for delayed ballots — even increased turnout at the polls on Tuesday — due to the mail delays.

LaRose asked the congressional delegation to provide additional staffing through the weekend to deal with the influx of election mail rushing through the postal system.

Although elections officials largely agreed with Republican Gov. Mike DeWine’s decision to close the polls last month under a health emergency, they are worried that the state legislature’s tight timeline to administer an all-mail election was too lofty a goal.

“At this point, there’s really nothing that can be done,” Aaron Ockerman, the executive director of the Ohio Association of Election Officials told ABC News. “That’s not a realistic timeframe. That’s a statutory timeframe. But certainly as we look into the future, relief from that and giving voters more time to get their ballots into the board of elections, would be very, very helpful.”

“The bottom line is, it’s unprecedented because we just don’t know who’s going to not get a ballot [in the mail] and want to show up,” Ockerman said of the limited polling places on Tuesday.

Voting rights groups are concerned that without litigation to combat the results of a slow-moving postal system, some ballots will go uncounted.

“The legislature isn’t going to do anything unless they’re sued. So the hope is that there is a lawsuit,” said Yvette Simpson, the executive director of Democracy for America, a former Cincinnati city councilwoman and a ABC News contributor.

“I would say, big picture, that this is also a test case for November. We’re hearing that we will have a resurgence in the fall of COVID,” Simpson said, adding that her group is evaluating what a feasible standard will be for voting-by-mail nationwide for the general.

LaRose initially issued a directive to election officials statewide that in-person voting would take place on June 2, which was overturned by the state legislature. Lawmakers settled on April 28 as the deadline to return ballots.

Even without postal service delays, some speculated at the outset of election changes, including LaRose and local officials, the turnaround would not be feasible.

“The Secretary of State should have mailed a ballot to every registered Ohio voter weeks ago. The process he put in place was unnecessarily arduous and will directly result in less votes cast,” said Ohio Rep. Tim Ryan in a statement to ABC.

Turnout is low for a major election year, Ockerman said. Based on the number of absentee ballot requests alone, turnout is around 22%, or half of what the state saw in 2016.

“Additionally, the USPS is in dire straits financially, but instead of offering assistance, President Trump is threatening to veto any bill that helps the Postal Service. Trump and the Congressional Republicans need to get off the sidelines and help. We’ve got elections to run and essential supplies that need to be delivered, not to mention the health and welfare of the postal workers and letter carriers on the front lines during this health crisis,” Ryan said.

In an email obtained by ABC News, the USPS wrote to election officials that the state’s benchmark for ballot turnout will be difficult to meet, possibly leaving ballots undelivered.

“The state’s deadline for mailing out and returning ballots largely falls outside of the Postal Service’s delivery standards,” the email reads. “As a result, please be advised that while we will endeavor to deliver ballots as quickly as possible, there is a strong likelihood that the timing for mailing out ballots may not allow adequate time for voters to receive the ballot and return it by mail in time to meet the state’s postmark deadline or in some instances, in time for voters to hand deliver their ballots ahead of polls closing on Tuesday.”

Catherine Turcer, the executive director of Common Cause Ohio, said that for vote-by-mail to be successful in Ohio, should that be the default in November, the process needs to be streamlined. That means eliminating the additional back-and-forth of submitting an absentee ballot application.

Five states already use vote-by-mail as the primary driver for their elections, and automatically send every registered voter a ballot.

As Congress works to pass new funding packages to offset the economic impacts of COVID-19, experts have called for more money to change the vote-by-mail process and for additional funding for USPS.

Rick Hasen, a professor of law and political science at the University of California- Irvine, told ABC News that without additional funding to support vote-by-mail, November’s general presidential election could pose challenges, even as states try their hardest to implement a functional election during a pandemic.

“You can’t have an effective by-mail system without an effective, functional Postal Service,” Hasen said. “Even for those states in which the return of balance happens at voting centers or in government dropboxes, mail is still essential for getting ballots to voters, getting other voting materials to voters. It’s really unthinkable that we could run an effective election in November without a functioning Postal Service.”