Dozens of people who are not U.S. citizens were allowed to register to vote due to a glitch in Pennsylvania's electronic driver's license system, a Philadelphia election official said Wednesday.

Al Schmidt, a Republican who sits on Philadelphia's three-member election commission, told reporters that at least 168 noncitizens -- who are legal residents of the U.S. -- had registered to vote in the city through the licensing system.

Philly.com reported that 317 such illegal voters have contacted the commission since 2006 to have their registrations canceled. Of those, Schmidt's office said that 220 were registered to vote from 2006 to 2017. Forty-four voted in one election and 46 voted in more than one election.

"This is a real concern," Schmidt said. "It is harmful to election integrity, and it is harmful to members of the immigrant community who are applying for citizenship. If you've registered to vote in the U.S., and you're not a citizen, it's potential grounds for the denial of your citizenship application."

Schmidt said that many more noncitizens could have mistakenly registered through the system, both in Philadelphia and elsewhere in Pennsylvania. However, he pointed out that no municipal election was close enough to have potentially been affected by improper voting.

Schmidt also said that the cases likely did not rise to the level of voter fraud because of the apparent lack of intent by the registrants.

"All voter fraud is an irregularity; not all voter irregularities are fraud," he said. "Regardless of the intent, the damage is still the same."

The Pennsylvania Department of State said it is working to fix the system and was aware of the problem before Schmidt contacted it in July. A spokeswoman could not immediately say when the department first became aware of the issue.

The department is looking into the total number of mistakenly registered voters and could not provide an estimate, the spokeswoman said.

Last fall, during a legislative hearing on the integrity of the state's voting systems, Secretary of State Pedro Cortes, a Democrat, acknowledged that someone who is not a citizen "may inadvertently register" while getting or updating a driver's license, according to a transcript of the hearing.

Some 6.1 million people voted in Pennsylvania in November's presidential election, including more than 700,000 in Philadelphia. Donald Trump, a Republican, won Pennsylvania; Hillary Clinton, a Democrat, won Philadelphia.

The registration problem stemmed from electronic touch screens in state driver's license centers that were programmed to give users the option to register to vote while getting new or updated licenses. The system showed noncitizens the voter registration option, even though they had already provided information showing that they were not citizens, officials said.

"For the majority of these people, it’s completely plausible to believe they thought they were eligible to vote," Schmidt said.

In August 2016, the department took a step to try to prevent such registrations. It changed the software so that users are immediately asked if they are U.S. citizens. The process stops if a user answers "no," the department said.

It said it is working on creating a new touch-screen system in which a noncitizen would not see the motor voter screens at all, the department said.

The motor voter system may not be the only problem in Pennsylvania. Schmidt said he discovered 52 other noncitizen legal immigrants who registered to vote through other means, including paper voter registration applications. The Department of State is looking into that, as well, the spokeswoman said.

The Associated Press contributed to this report.