GOP Rep. Jeff Flake (Ariz.) will announce Monday that he is running for the Senate in 2012.
According to a Republican source familiar with his plans, Flake will hold an 8 a.m. Mountain Time news conference in Phoenix to declare his candidacy to replace Sen. Jon Kyl (R-Ariz.), who is retiring. The seventh-term congressman has long been rumored to want a spot in the upper chamber.
He's also a favorite of the Club for Growth, which has already publicly urged him to jump into the race.
Flake could face a crowded GOP field. A number of Republicans, including Rep. Trent Franks (Ariz.) and former Rep. J.D. Hayworth (Ariz.), have said they are also considering running.
Democrats are also targeting Kyl's seat as a pickup opportunity, and some party members in Arizona are holding out hope for the recovery of Rep. Gabrielle Giffords (D-Ariz.), who, before she was shot at a public event in January, told staff she would run for Senate if Kyl retired.
This post was updated at 7:40 a.m.