Pennsylvania Gov. Tom Wolf on Friday ordered counties that plan to replace their electronic voting systems to buy machines that leave a paper trail — a safeguard against hacking — but his budget doesn't include any money to fund the replacement of the state's aging, increasingly vulnerable fleet.

The Democrat's administration said the move to require that new systems include a paper backup will increase the security of voting systems and make balloting easier to audit.

"This directive will ensure that the next generation of the commonwealth's voting systems conforms to enhanced standards of resiliency, auditability and security," Acting Secretary of State Robert Torres said in a statement.

The Wolf administration said in a statement later Friday that it's working on a comprehensive overhaul of Pennsylvania's election apparatus, including its voter registration database. Hackers scanned voter registration databases around the nation before the 2016 presidential election.

The state, however, is not requiring counties to discard their old equipment, at least for now. The directive only requires them to buy machines with a paper backup if they decide to switch systems. Nor does the Wolf administration's budget plan , released this week, include any new money to help counties replacing their aging systems.

Marybeth Kuznik, the founder and executive director of VotePA, a nonprofit advocacy group that opposes paperless electronic voting, said counties don't have the money to buy new machines.

"The General Assembly needs to step up to the plate and budget for this," she said.

Nevertheless, Kuznik, a longtime election judge outside Pittsburgh, called Friday's order "a huge step forward for Pennsylvania, for better elections. Just huge."

Pennsylvania is one of 13 states where most or all voters use antiquated machines that store votes electronically without printed ballots or other paper-based backups that could be used to double-check the vote, according to researchers at New York University's Brennan Center for Justice.

So-called direct-recording electronic machines make it almost impossible to know if they've accurately recorded individual votes or if anyone tampered with the count.

Election officials in 41 states plan to use older machines in the 2018 midterm elections, the Brennan Center said this week. Some of those machines have paper backups. Most election officials surveyed by the Brennan Center said they lacked funds to replace machines that are more than a decade old.

"In the world's leading democracy, we can't take the position that we can't afford to do elections correctly," said David Hickton, a former federal prosecutor and founding director of the University of Pittsburgh Institute for Cyber Law, Policy, and Security. "The recent attacks on our election should concern everybody, and a priority has to be placed on doing what is necessary."

Most Pennsylvania counties replaced their machines more than a decade ago with money appropriated by Congress for election upgrades. With those machines at or near the end of their expected lifespans, the County Commissioners Association of Pennsylvania is pushing for state and federal funding to help counties buy replacements. New voting machines can run $3,000 apiece.

The vast majority of Pennsylvania's fleet of more than 20,000 electronic voting machines leave no paper trail, according to a 2014 tally by state election officials.

Wolf's Department of State said it has "made no determination" on whether it will eventually bar the use of the antiquated machines, raising the possibility that such a move is under consideration. A spokeswoman did not immediately respond to an email seeking clarification.

Virginia banned the use of touch-screen voting machines in November's gubernatorial contest over concerns the equipment could be hacked.

The federal government in September told election officials in at least 21 states, including Pennsylvania, that hackers targeted their systems before the 2016 presidential election. At the time only Illinois reported that hackers had succeeded in breaching its systems. The U.S. Department of Homeland Security has said there's no evidence that vote tallies or registration databases were altered.