US Democratic presidential hopeful Beto O'Rourke has announced he is ending his campaign.
Beto O'Rourke Photo: AFP
The former Texas congressman tweeted: "Our campaign has always been about seeing clearly, speaking honestly, and acting decisively.
"In that spirit: I am announcing that my service to the country will not be as a candidate or as the nominee."
Mr O'Rourke, 47, began his run for president in March after losing his 2018 bid to oust Texas Republican Senator Ted Cruz.
In that Senate race, he did better than any Democrat had in Texas for decades, running a campaign that invigorated the party nationwide and drew comparisons with former President Barack Obama.
His passionate delivery along with his good looks and background as a skateboarder and a punk rocker endeared him to liberals across the country.
In August he attracted media attention when he accused U.S. president Donald Trump's anti-immigrant rhetoric for being partly responsible for an upswell of hatred and racial divisions that inspired a mass shooting that killed 22 people at a Walmart in El Paso, Texas.
But Mr O'Rourke struggled to carry that energy into a White House race crowded with more than 20 Democratic candidates.
On Friday (local time) he said his campaign did not have "the means to move forward successfully".
Speaking in Des Moines, Iowa, Mr O'Rourke thanked his supporters, many of whom were clearly disappointed.
He vowed to support the Democratic nominee who will challenge Republican president Donald Trump in the 2020 race for the White House.
"We're right in the middle of this fight," he said.
What went wrong?
During his 2018 Senate race, the former Texas congressman was fundraising like a top-tier presidential candidate.
Beloved by Democrats across the country for his youthful energy, his passionate speeches became viral sensations.
But his obvious political skills in his home state did not translate on to the national stage, however, where a lack of campaign organisation and an inability to stand out on a crowded debate stage cost him dearly.
As the initial buzz over his campaign began to subside, Mr O'Rourke tried to reboot his candidacy.
He began to focus on gun control, and vowed to remove assault-style weapons from private ownership, saying in one televised debate: "Hell yes, we're going to take your AR-15s."
Donald Trump Photo: AFP
But he could not catch up with front-runners like former Vice-President Joe Biden, Massachusetts Senator Elizabeth Warren and Vermont Senator Bernie Sanders.
Mr O'Rourke also found himself leap-frogged by another young, charismatic candidate - 37-year-old Pete Buttigieg, mayor of South Bend, Indiana.
In the latest opinion poll by New York Times and Siena College on Friday, Mr O'Rourke drew the support of just 1per cent of voters in the crucial early-voting state of Iowa.
Mr O'Rourke had been urged by donors to drop out of the presidential race and run against Texas Senator John Cornyn, who is up for re-election next year. But the O'Rourke camp reiterated in a statement on Friday night that he did not plan on standing for the Senate again.
Mr O'Rourke is not the only once-promising Democratic candidate who is struggling - California Senator Kamala Harris this week scaled back her campaign, firing some staffers and shuttering offices in another key, early voting state, New Hampshire.
After Mr O'Rourke dropped out on Friday, Mr Trump mocked him in a tweet.
- BBC