Washington — The Trump administration is dispatching top officials to help campaign for Iowa Republican candidates over the coming days, including Treasury Secretary Scott Bessent, U.S. Trade Representative Jamieson Greer, Small Business Administration Administrator Kelly Loeffler, Veterans Affairs Secretary Doug Collins and U.S. Ambassador to NATO Matt Whitaker, sources familiar with the matter told CBS News.

The Iowa State Fair, which starts Thursday and runs through Aug. 23, is a pivotal window of opportunity for candidates on the campaign trail. 

Facing tough races are Republican Rep. Mariannette Miller-Meeks, who is running against Democrat Christina Bohannan in Iowa’s 1st Congressional District, and Rep. Zach Nunn, who is being challenged by Democrat Sarah Trone Garriott in Iowa’s 3rd Congressional District. Republican Rep. Ashley Hinson is running for U.S. Senate against Democrat Josh Turek. 

Their schedules in Iowa were not immediately available. 

House Majority Leader Steve Scalise was in Iowa Wednesday, along with the head of the Republican National Committee, Joe Gruters, and Republican Reps. Jason Smith of Missouri, Pete Stauber of Minnesota, and Glenn Grothman of Wisconsin.

This is a developing story and will be updated.