With the midterm elections less than a month away, a strong majority of Americans are concerned the nation's voting systems might be vulnerable to hackers, according to a poll released Wednesday.

That is roughly unchanged from concerns about election security held by Americans just before the 2016 presidential election, but with a twist. Two years ago, it was Republicans who were more concerned about the integrity of the election. This year, it's Democrats.

The survey from The University of Chicago Harris School of Public Policy and The Associated Press-NORC Center for Public Affairs Research found that Democrats have grown increasingly concerned about election security while Republicans have grown more confident.

By 58 percent to 39 percent, Democrats are more likely than Republicans to say they are very concerned about hackers affecting U.S. election systems. That represents a flip from the results of a similar survey taken in 2016.

The same partisan divide exists in the confidence Americans hold in the accuracy of vote tallies for the upcoming midterm elections. Republicans are more confident, a reversal from 2016.

Nearly 8 in 10 Americans are at least somewhat concerned about potential hacking, with 45 percent saying they are extremely or very concerned. Just 22 percent have little or no confidence that votes will be counted accurately. Those results are similar to a poll conducted in September 2016.

"People are right to be concerned," said Lawrence Norden, a voting system expert with The Brennan Center for Justice at New York University School of Law. "The critical thing I hope people understand is that there are lots of things that can be done to deal with cyberattacks on our election infrastructure, and there has been a lot done since 2016."

Federal, state and local election officials have scrambled over the past two years to shore up cybersecurity defenses of election systems, improve communications about potential cyber threats and reassure the public that all steps are being taken to protect the vote. Congress has funneled $380 million to states to help cover the costs of adding cybersecurity personnel, conduct training and upgrade equipment.

Much of that is in response to the 2016 presidential election.

U.S. intelligence officials say Russian operatives launched a multipronged effort to interfere with the 2016 election, including a sophisticated social media campaign, the hacking of Democratic National Committee emails and the electronic scanning of state election networks. Illinois' voter registration system was breached, but authorities say no information was altered or deleted.

This year, the nation's intelligence agencies warned that Russia and others remain interested in interfering in U.S. elections, but have emphasized that they have detected no targeting of election systems on the level seen ahead of the 2016 vote.

Nearly 80 percent of Americans say they are at least somewhat concerned about the hacking of voter registration systems, voting equipment and final election results, with at least 4 in 10 saying they are extremely or very concerned about each.

Among the biggest concerns of cybersecurity experts is the use, in some states, of touchscreen voting machines that do not produce a paper record. Other such machines do allow voters to verify their selections and create a paper trail for a reliable audit of election results.

A U.S. Senate report earlier this year urged states to replace their paperless machines, which were used by roughly one of every five voting jurisdictions nationwide in the 2016 election. Five states — Delaware, Georgia, Louisiana, New Jersey, and South Carolina — are expected to rely on electronic machines without paper receipts during the upcoming midterm elections. At least eight others will use those machines in some counties.

The poll found that just 21 percent of Americans saying they are extremely or very confident in paperless machines and another 45 percent saying they are somewhat confident. By comparison, 88 percent expressed at least some level of confidence in electronic voting machines that provide a paper receipt and 84 percent for paper ballots scanned into a machine.

The $380 million sent to states from the federal government was not enough to cover the costs of replacing all such machines.

Jennifer Blomqvist, a 47-year-old administrative assistant from Decatur, Georgia, said she is concerned voting systems remain vulnerable to hackers and would support a system in Georgia that produced a paper record.

"As long as they are electronic, anybody and everybody can go in and hack," Blomqvist said, adding she still hopes all votes will be counted accurately. "I want to trust the system, for as old as it is."

The survey also found limited support for online voting (28 percent in favor) and for the exclusive use of mail-in ballots (19 percent in favor). Younger voters, those age 18 to 29, are more supportive of online voting than older adults. Even so, less than half of young adults favored online voting.