A Wisconsin official has discouraged state workers from volunteering information about free IDs available under a controversial voter identification law that critics complain is designed to suppress votes, a memo leaked on Wednesday showed.

The memo, provided to the press by Democratic State Senator Jon Erpenbach, was likely to fan concerns among critics of the Republican-backed law that it aimed to suppress votes of thousands of otherwise eligible Wisconsin voters.

In the memo, a top aide in the state transportation department told staffers in the motor vehicle department, which is responsible for issuing the free IDs, to “refrain from offering” them to customers who do not specifically ask for them.

“Questions on what kind of ID is needed for voting,” the aide, Steven Krieser, wrote in the July 1 memo, “should be directed to the Government Accountability Board.”