The speaker of the Oklahoma House of Representatives announced his candidacy for the GOP nomination for the U.S. Senate on Wednesday, ABC News reported.

State Rep. T. W. Shannon, R-Lawton, will run for the seat left vacant by U.S. Sen. Tom Coburn once he steps down from his position two years early.

"Over the last six years, I have seen so many of our rights and freedoms under assault, it makes me seriously concerned about what kind of country my children will inherit," Shannon said to a crowd at the Tulsa Historical Society.

Minutes before his announcement, U.S. Rep. Jim Bridenstine issued a statement saying he would not be running for the seat.

"Since Dr. Tom Coburn's retirement announcement, I have been honored and overwhelmed by encouragement to succeed him as Oklahoma's senator," Bridenstine said. "After giving this matter serious consideration and prayer, my family and I have decided I will not run in the special election to complete Dr. Coburn's term."

Bridenstine was elected to the U.S. House in 2012 after defeating Republican incumbent Rep. John Sullivan.

Shannon faces U.S. Rep. James Lankford and two others for the Republican nomination. So far, no Democratic candidates have announced a bid to run. As ABC reported, a Democrat has not been elected to an open seat in Oklahoma since 1978 and Republicans are heavily favored to fulfill the seat.

The state House speaker also thanked Bridenstine for his support and mentioned that the two had been in contact within the past few weeks.

"He's a good guy who has stood up and been a leader in the House, and certainly him opening the door for me to seek even more support has been helpful to the campaign," Shannon said.

A member of the Chickasaw Nation, Shannon, 35, was the first African-American and youngest speaker elected to the Oklahoma House of Representatives last year.