Roughly 400 noncitizens voted in New Jersey after about 6,600 residents were improperly registered to vote between June 2023 and June 2024 because of a software error at the Department of Motor Vehicles, Gov. Mikie Sherrill announced on Tuesday.

All of the people affected had disclosed that they were not citizens when registering for either a driver’s license or ID, but were nonetheless placed on the voter rolls in error.

“These individuals answered ‘no’ when asked on a keypad whether they were a U.S. citizen when applying for drivers’ licenses and identification cards, but through no fault of their own, the system registered them anyway,” the governor said in a statement.

Fewer than 400 of the residents who were improperly registered have since voted, the governor said, and all 6,600 people will be removed from the voter roles.

The New York Times could not independently verify those figures.

Ms. Sherrill, a Democrat who took over in January, held a news conference at 12:15 p.m. to discuss the error tied to a software vendor that is being phased out of use in New Jersey.

State officials became aware of the error last week and began an immediate investigation into what had happened.

“I want to underscore how seriously I take this matter,” Ms. Sherrill said.

The governor, in the statement, said that she was “appalled by the reckless failures that allowed this to happen.”

“I believe the integrity of our elections is fundamental to our democracy,” she added.

This is a breaking news story. Check back for updates.