U.S. Rep. Ken Buck (R-CA) leaves the House Chamber as the House of Representatives holds a vote to impeach Homeland Security Secretary Alejandro Mayorkas, at the U.S. Capitol on February 06, 2024 in Washington, DC. 

Rep. Ken Buck, R-Colo., who announced last fall he would not seek re-election, said Tuesday he will resign from Congress at the end of next week, further shrinking the GOP's already razor-thin majority.

"Today I am announcing that I will depart Congress at the end of next week," Buck said in a statement. "I look forward to staying involved in our political process, as well as spending more time in Colorado and with my family."