U.S. Rep. Pete Olson, R-Sugar Land, announced Thursday afternoon that he is retiring from Congress at the end of his term.

The retirement sets up what will likely be one of the most competitive House races in the country. Olson narrowly won reelection last year against Democrat Sri Kulkarni, who is running again.

Olson, who was first elected to Congress in 2008, announced his retirement in a news release.

“Protecting our future and preserving our exceptional nation are the reasons I first ran for Congress," he wrote. "Now, it’s time for another citizen-legislator to take up this mission, not to make a career out of politics, but to help lead in the cause of empowering our people, defending our liberties, and making sure America remains the greatest nation in history.”

Among Republicans who could run for the seat, Fort Bend County Sheriff Troy Nehls is an immediate prospect. He explored challenging Olson last year and recently announced he wasn't running for reelection as sheriff, keeping the door open to a TX-22 campaign.

Olson is a graduate of Rice University and the University of Texas School of Law. On the day he took the bar exam, he enlisted in the Navy and served as an aviator during the Gulf War. He went on to serve as a staffer to Republican U.S. Sens. Phil Gramm and John Cornyn.

During his time in Congress, he has served on the House Energy and Commerce Committee. He championed the Keystone XL pipeline and focused much of his attention on NASA's Johnson Space Center. Hurricane Harvey hit his southwestern suburban Houston district hard. To help draw attention to the Texas delegation's advocacy for hurricane relief, Olson went around Capitol Hill wearing an Astros jersey over his dress shirt.

Attorney Nyanza Davis Moore and Pearland City Councilman Derrick Reed are also running for the Democratic nomination.

While once a conservative stronghold, the district's political future is uncertain. Olson won reelection last November by a mere 5 percentage points. House Democrats made clear early this cycle they plan to mount a fierce challenge against him.

The chairman of the House GOP campaign arm, U.S Rep. Tom Emmer, R-Minnesota, released a statement on Olson's decision.

"I’d like to thank Pete for his years of service to Texas and the nation and wish him well in his retirement," he said. "Whoever the socialist Democrats nominate will be forced to defend their party’s radical agenda of socialized medicine and killing oil and gas jobs with the Green New Deal in a solid Republican district.

“This will remain a Republican district for the foreseeable future."

A spokesman for the Democratic counterpart committee released his own bullish statement about the seat.

“Republicans across Texas are terrified of losing their seats in 2020 and we can’t blame Pete Olson for choosing to retire instead of being thrown out of office next year," said spokesman Avery Jaffe. "That’s why we added him to our Republican Retirement Watch List in February."

"As the [Democratic Congressional Campaign Committee] continues to invest in Texas, Washington Republicans like Olson are thinking twice about pouring their time and money into seats that used to be safe bets. One of the most diverse districts on the battlefield, Democrats can win this open seat and we look forward to Congressman Olson spending his golden years deep in the heart of Texas."

Patrick Svitek contributed reporting.