Colorado Springs Mayor Lionel Rivera says he'll run for retiring U.S. Representative Joel Hefley's seat.
He says he'll officially announce his candidacy to replace the 10 term congressman on Thursday.
Rivera, a former Army captain, says he's the only Republican candidate that has a military background.
Meanwhile, Hefley endorsed former staffer Jeff Crank for the Fifth Congressional District.
Crank worked for Hefley from 1991 to 1998, including serving as his administrative director.
He's also a former president of the Greater Colorado Springs Chamber of Commerce.
Also running for the G.O.P. nomination former El Paso County Sheriff John Anderson, state Senator Doug Lamborn and attorney Duncan Bremer.
Candidates running for the Democratic nomination are former Air Force Academy professor and Gulf War veteran Jay Fawcett and rancher Curtis Imrie, who won the party's nomination in 2002.