DES MOINES --- Sen. Joni Ernst is set to appear on the campaign trail Monday with Republican presidential candidate Marco Rubio with only a week until the Iowa caucuses kick off.

Ernst, who maintained she is remaining neutral in the race, will be introducing Rubio at an event in Des Moines.

"Our nation faces exponential threats, and over the past year, I've had the opportunity to work alongside Marco Rubio on issues critical to our national security," Ernst said in a statement. "Marco is not only a strong conservative and a good friend, but someone that I trust to secure our country."

"As I have made clear, I will not be endorsing in the caucuses; that is a promise I will maintain to Iowans," Ernst continued. "On Monday, I look forward to introducing Marco to more Iowans and discussing the important work needed to keep our nation safe and secure."

The news of Ernst's appearance comes a day after longtime Iowa Sen. Chuck Grassley appeared at Donald Trump's rally in Pella. Grassley is also reportedly set to introduce Cruz at a post-debate campaign event on Friday evening in Vinton, according to a Cruz spokeswoman.

The Rubio campaign is looking to capitalize on momentum from Saturday, when they snagged endorsements from the Des Moines Register, Iowa's largest newspaper, and the Sioux City Journal over the likes of Donald Trump and Sen. Ted Cruz, who are currently topping polling in the state according to the latest RealClearPolitics average.