HARRISBURG, Pa. (AP) — Pennsylvania election officials said Wednesday that there is no evidence to back up a claim that more than 100,000 noncitizen immigrants had been registered to vote in the state, responding to a conservative group's lawsuit in federal court.

The Department of State, in a statement to The Associated Press, said it is reviewing data and that the figure "is not confirmed by any substantive analysis by the Department. It is not a credible figure and there is no reason to believe it to be accurate."

The department, which oversees elections in Pennsylvania, did not, however, give a figure as to how many noncitizens it believes are registered to vote, which is illegal. The department's acting secretary, Robert Torres, has said the agency was working to ensure that any noncitizens who had registered vote would not be able to cast a ballot in the May 15 primary.

More than 8.4 million people are registered to vote currently, according to department data.

State officials have acknowledged that a longstanding glitch in the design of Pennsylvania's electronic driver's licensing system — going back to its start in the mid-1990s — had allowed noncitizen immigrants to inadvertently register to vote. The Department of Transportation said it had fixed the glitch as of late last year.

The lawsuit, filed Monday in federal court by the conservative Public Interest Legal Foundation, said the state is violating the National Voter Registration Act by blocking its access to records of Pennsylvania's efforts to identify and remove noncitizen immigrants from voter registration lists.

A state lawmaker, House State Government Committee Chairman Daryl Metcalfe, R-Butler, is seeking similar records under Pennsylvania's Right-to-Know Law.

The lawsuit cites the December testimony of a Republican election official from Philadelphia, who told a state Senate committee that the Department of State had found more than 100,000 matches when comparing driver's license numbers with noncitizens' designations to voter records with driver's license numbers.

The Philadelphia election official, Al Schmidt, went on to tell the committee that that the actual number of noncitizens registered to vote may be lower, testimony the lawsuit did not cite.

"Because some people have become citizens along way, or maybe they got a driver's license number and then some months later became a citizen and then registered to vote," Schmidt told the committee. "But we're not talking about an insignificant number here. We're talking about a potentially very significant number of thousands and tens of thousands."

A similar process played out in Florida several years ago, amid a flurry of lawsuits objecting to a potential purge of voter rolls that could sweep out eligible voters. In a search for noncitizen immigrants, state officials initially found 180,000 people suspected of being ineligible to vote when comparing databases of registered voters and driver's licenses.

Florida officials later assembled a purge list of more than 2,600 names in 2012. But it was beset by inaccuracies and a revised list of 198 names of possible noncitizens was produced through the use of a federal Homeland Security Department citizenship database.

In December's hearing, Torres told senators that the Department of State had hired "outside professionals" to help compare and analyze driver's license records and voter registration records. The agency then must validate its information with county elections records and contact anyone who is affected, Torres said.

State officials said last fall that noncitizens may have cast 544 ballots illegally out of more than 93 million ballots in 35 primary and general elections from 2000 through 2017 in Pennsylvania.

The illegal ballots were apparently cast by noncitizen immigrants who later reported themselves as having mistakenly registered, the department has said. The figure could drop as the department analyzes county records, department officials have said. The number of possibly illegal ballots comes to one in every 172,000.