U.S. Rep. Doug Lamborn is throwing his support behind U.S. Senate candidate Eli Bremer, one of seven Republicans hoping to challenge Democratic U.S. Sen. Michael Bennet.

Lamborn, who is serving his eighth term representing the El Paso County-based 5th Congressional District, is so far the only Republican member of Colorado’s congressional delegation to make an endorsement in the crowded U.S. Senate primary.

“I have known Eli Bremer for many years, living in the same community,” Lamborn said in a statement. “Eli has been an Air Force officer, a pentathlete in the Olympics, a successful El Paso County Republican chairman, and an entrepreneur. Most of all, Eli Bremer is a candidate who can actually unite statewide and national support and win in November.”

Lamborn is the third sitting congressman to endorse Bremer this week, following U.S. Reps. Jim Banks of Indiana and Neal Dunn of Florida. Last fall, U.S. Rep. Mike Garcia, who represents a swing district in California, endorsed Bremer.

Bremer is seeking a spot on the June primary ballot at Saturday’s state Republican assembly in Colorado Springs, where it will take support from at least 30% of the delegates to advance to the primary.

The other Republicans running for the U.S. Senate include state Rep. Ron Hanks, R-Cañon City; real estate developer and former Fort Collins City Councilman Gino Campana; former talk radio host and nonprofit founder Deborah Flora; business consultant and former congressional nominee Peter Yu; and, political science professor Gregory Moore.

Construction company owner Joe O’Dea, a first-time candidate, has already qualified for the GOP’s primary ballot by petition.

Lamborn is facing three primary challengers in his bid for a ninth term: state Rep. Dave Williams, R-Colorado Springs, Navy veteran Rebecca Keltie and business owner Andrew Heaton. Williams won top-line designation at last weekend’s 5th CD assembly, and Lamborn and Keltie have qualified for the primary by petition, while Heaton is awaiting word on whether petitions he submitted last month contain enough valid signatures.

Bremer told Colorado Politics in a written statement that he is grateful to receive Lamborn’s support.

Said Bremer: “He has been a long-time conservative leader in the U.S. House of Representatives on issues such as protecting the unborn, supporting our vast military and veteran community in Colorado Springs, and protecting our 2nd amendment rights. I look forward to fighting alongside him on many issues important to Colorado, including to keep Space Force right here in Colorado. Congressman Lamborn has served our Colorado Springs community honorably for nearly two decades in Washington. Congressman Lamborn knows how to win and represent Coloradans, and I am honored by his trust in my ability to do that.”