HARRISBURG — 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 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 to vote would not be able to cast a ballot in the May 15 primary.

More than 8.4 million people are registered to vote, the department said.

State officials have acknowledged that a long-standing 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 was filed Monday in federal court by the conservative Public Interest Legal Foundation.