Rep. James Lankford, the No. 5 House Republican, will run in a special election for the seat being vacated by Sen. Tom Coburn, R-Okla., Lankford announced Monday.

"After a great deal of thought, prayer and discussion with my family, I feel led to continue my Oklahoma common sense and principled approach to attack the deep problems in the United States Senate," Lankford said, citing the federal health care law and debt as issues upon which he intends to focus.

Lankford announced his bid at a press conference in Oklahoma City. The primary election will be held June 24.

Lankford has served in the House only since 2011, but he has risen quickly through the ranks to lead the Republican Policy Committee. If he won the Republican primary, he would have a relatively level path to winning the GOP-favored Senate seat.

But complicating Lankford's bid is the likely involvement in the primary of the Senate Conservatives Fund, an outside group that has been pushing Rep. Jim Bridenstine to run, and which emailed supporters Monday announcing it would not endorse Lankford. The group is known for spending big in GOP primaries in safe Republican Senate races that often do not draw substantial investment from national Republicans.

Bridenstine has not announced whether he will run for Coburn's seat, and his office last week declined comment. Meanwhile, Rep. Tom Cole, R-Okla., a close ally of House Speaker John Boehner, announced he will not run for Senate.

Coburn announced last week that he will retire at the end of this Congress, accelerating his previous plans to leave the Senate by roughly two years and setting off an unexpected scramble by those looking to fill his seat. Coburn, who has prostate cancer, said his health was not a factor in his decision.