DES MOINES, Iowa (AP) — A Republican strategist has challenged the filing paperwork of the only GOP candidate seeking to run against Gov. Kim Reynolds in the upcoming primary. The Iowa Secretary of State’s Office says a formal challenge was filed Wednesday against Republican Ron Corbett’s paperwork to be on the June 5 primary ballot.

Corbett submitted petition signatures last week. Craig Robinson, a former political director for the Republican Party of Iowa, claims Corbett’s campaign turned in duplicate signatures that put the former Cedar Rapids mayor below the required signature threshold.

A review board that includes the secretary of state will meet as early as next week to discuss evidence and issue a decision. A Corbett aide says the campaign is confident it has enough signatures. Reynolds formally launched her gubernatorial campaign this month. Six Democrats and two libertarians are also running for governor.