Officials in Lancaster County in the swing state of Pennsylvania say they identified hundreds of potentially fraudulent voter registration applications.

"Suspected fraudulent voter registration forms were dropped off at the Board of Elections Office in two batches at or near the deadline for submission," the board said in a statement on Friday. "There are approximately 2,500 voter registration applications total in these two batches."

It's unclear how many of the applications in the two batches are alleged to be fraudulent.

In its statement, the board stressed that county elections are secure and that flagging the potential fraud indicates the "systems worked." Republican-leaning Lancaster County has more than 360,000 registered voters.

The statement said concerns "were raised during the staff's normal process to review and enter applications into [a state database] and law enforcement was alerted."

In a news conference Friday with board members, Lancaster County District Attorney Heather Adams said numerous applications appeared to have the same handwriting and other details, like addresses, appeared incorrect on some applications.

Adams said the investigation is ongoing, and wouldn't comment on who may have dropped off the potentially fraudulent forms.

NPR has previously reported that paid canvassing operations have on occasion included fraudulent signatures that were caught.