Kansas hasn’t decided when to start issuing a new type of driver’s license to residents who voluntarily document their U.S. citizenship when renewing their licenses.

Department of Revenue Secretary Nick Jordan said Monday the timing is uncertain because officials aren’t sure how the federal government will enforce a 2005 anti-terrorism law aimed at making state driver’s licenses more secure.

Jordan has been criticized because earlier this year the department backed off plans to require citizenship papers from people renewing their licenses.

Kansas requires new voters to document their citizenship, and some lawmakers expected voters to take care of it while renewing their licenses.

Jordan said federal officials say Kansas is complying with the anti-terrorism law if residents can voluntarily provide citizenship documents and receive a different license.