Updated at 8:55 p.m. with details throughout.

WASHINGTON -- San Antonio Rep. Will Hurd, the House's sole black Republican, shook the political landscape in both Texas and D.C. late Thursday by announcing that he will not seek reelection next year in his sprawling border district.

Hurd, a former CIA agent, said he wanted to "pursue opportunities outside the halls of Congress to solve problems at the nexus between technology and national security."

"I want to use my knowledge and experience to focus on these generational challenges in new ways," he said in a news release. "It was never my intention to stay in Congress forever, but I will stay involved in politics to grow a Republican Party that looks like America."

The surprise exit of Hurd, a sometimes critic of President Donald Trump, carries deep political consequence, particularly for the GOP's hopes of winning back the House.

Hurd is the third Texas Republican in the last week to announce his retirement at the end of this term. He followed Rep. Pete Olson of Sugar Land and Rep. Mike Conaway of Midland, only furthering the monumental turnover seen in recent years in the Texas congressional delegation.

But Hurd's announcement stands out, given that he represents the only true swing district in Texas.

He won reelection last year against Democrat Gina Ortiz Jones by less than 1,000 votes. She's running again this time around, and both Republicans and Democrats are expected to battle hard for a district that's more than 70% Hispanic and shares 820 miles of border with Mexico.

Just ask the Texas Democratic Party.

"The simple facts are that hypocrite Trump Republican Will Hurd did not stand a chance in the 23rd congressional district," Manny Garcia, the party's executive director, said in a news release, adding that "Texas is the biggest battleground state."

Or do the same with the National Republican Congressional Committee, the House GOP's campaign arm.

"Contrary to what the pundits will tell you, this is an R+1 district and we will fight tooth and nail to ensure it remains in Republican hands in 2020," Minnesota Rep. Tom Emmer, the NRCC's chairman, said in a news release, praising Hurd as a "patriot."

Hurd had been elected three consecutive times, first in 2014, in a southwest Texas border district that had previously swung between the two parties.

He served on the House intelligence and appropriations committees -- two prime postings that reflect his standing. He was well-known in his district for meeting constituents at far-flung Dairy Queen locations and become a viral sensation in 2017 for taking a bipartisan road trip with Beto O'Rourke.

Perhaps because of his district's dynamics, Hurd distinguished himself as a sometimes dissenter of Trump, a fellow Republican who lost Hurd's district to Democrat Hillary Clinton.

He derided Trump's idea for a border wall, often saying that "building a 30-foot wall from sea to shining sea is the most expensive and least efficient way to do border security." He also proposed a bill to provide a permanent fix for unauthorized immigrants who had come to the country as children.

But Hurd's independent streak wasn't limited to immigration.

He last year took to the opinion pages of The New York Times to assert that Trump is being manipulated by Russian President Vladimir Putin. He then used his recent chance to question former special counsel Robert Mueller to highlight that Russian meddling attempts continue to this day.

He also often stuck out as the rare Republican to buck the GOP on key House votes, including a recent resolution condemning Trump's racist tweets about four Democratic congresswomen of color.

"Those tweets are racist and xenophobic," he told CNN, referring to Trump's suggestion that those lawmakers -- all American citizens, three of them born in the U.S. -- should "go back" home.

"I go into communities that most Republicans don't show up in order to take a conservative message," he said. "This makes it harder in order to take our ideas, and our platform, to communities that don't necessarily identify with the Republican Party."

He again stressed that point in his retirement announcement.

"Every American should feel they have a home in our party," he said.

Though his tactics sometimes irritated more hardline conservatives, most of Hurd's fellow Republicans gave him a wide berth to shore up his political vulnerabilities.

"Congressman Hurd has been a staunch advocate for his district in Washington -- frequently going against the grain for what he believed was right for his constituents," Texas GOP chairman James Dickey said, pledging that Republicans will fight to defend Hurd's seat.

But many Democrats were not convinced by Hurd, particularly after he said he would vote to reelect Trump. Jones, an openly gay Air Force veteran, made it a central part of her campaign to challenge Hurd's moderate image, criticizing votes like his to repeal the Affordable Care Act.

She has virtually not stopped campaigning since losing her election in November, already raising nearly $600,000 in campaign cash so far this year.

"After years of serving our country, first in the CIA and then in Congress, I respect Congressman Hurd's decision to serve in a new capacity," she said. "From San Antonio to Socorro and everywhere in between, Texans are ready for new leadership in Washington, and I'm ready to serve."

It remains to be seen who Republicans will nominate in next year's election. But some Democrats are already crowing, with Democratic Congressional Campaign Committee spokesman Avery Jaffe saying that "Democrats will win this seat."

"Republicans across the Lone Star State are terrified of losing their seats in 2020," he said. "Will Hurd just joined the list."

Even O'Rourke, Hurd's one-time road-tripping buddy, may have taken notice.

The former El Paso congressman, now running for the Democratic presidential nomination, took to Twitter an hour after Hurd's announcement. He didn't mention Hurd by name, instead simply positing that "Texas is in play" -- in the White House race and beyond.

"We're going to win it," he said.

Tom Benning contributed to this report from Washington and James Barragan contributed from Austin.