Washington election officials announced a preliminary review of a federal list of more than 400 alleged noncitizen voters has already uncovered U.S. citizens, inactive voters and people who are not currently registered. The revelation renews concerns about the accuracy of the Trump administration’s expanding effort to identify supposedly ineligible voters.

Secretary of State Steve Hobbs (D) disclosed the findings Wednesday in a blistering response to the Department of Justice (DOJ), which this week threatened litigation unless Washington stopped processing ballots tied to people on a list supplied by the Department of Homeland Security.

“A preliminary investigation confirms what your letter acknowledges: This list includes United States citizens and is not reliable,” Hobbs wrote. He said refusing to process a registered voter’s ballot without individualized proof of ineligibility would be “both irresponsible and illegal.”