TOPEKA, Kan. (AP) — Kansas Secretary of State Kris Kobach has used new power granted to his office by legislators this year to charge three voters with illegally casting ballots while voting in another state.

Meanwhile, those same new rules have resulted in the culling of more than six thousand incomplete voter registrations rejected at the polls.

Details of two cases filed by Kobach’s office in the Kansas City area’s Johnson County and one in northwest Kansas’ Sherman County became public Tuesday. They were filed late Friday. Kobach’s office filed 10 criminal charges in Sherman County against 64-year-old Lincoln L. Wilson. Officials in Kansas and Colorado said Wilson voted in both in 2010, 2012 and 2014.

In Johnson County, Kobach’s office filed three misdemeanor charges each against 61-year-old Steven K. Gaedtke, and his 61-year-old wife, Betty. Election officials said they voted in both Kansas and Arkansas in 2010. None of the defendants immediately returned telephone messages.

Kansas has seen its number of incomplete voter registrations decline by nearly 6,700 in less than two weeks as counties follow a directive from Secretary Kobach to cull their records.

Kobach’s office said Tuesday that the state had about 31,000 incomplete registrations as of Tuesday, compared to about 37,700 when the Republican secretary of state’s directive took effect on Oct. 2. The decline is nearly 18 percent.

Most incomplete registrations are for people who’ve failed to comply with a 2013 law requiring new voters to provide proof of their U.S. citizenship when registering.

Kobach imposed a new rule requiring county election officials to cancel registrations that are incomplete for more than 90 days.

He contends the proof-of-citizenship requirement prevents election fraud. Critics say it suppresses turnout.