Washington: Mitt Romney has won the Republican presidential primary in Texas and the remaining delegates needed to secure the party’s nomination.
With 1,086 delegates, Mr Romney only needed 58 to pass the 1,144 mark for the nomination. Texas awards 152 delegates proportionally.
In a statement, Mr Romney said he was “honoured” and “humbled” by the win.
He has been the presumptive nominee for several weeks as his rivals withdrew or suspended campaigning.
He is challenging Barack Obama for the White House in November.
In early returns, Mr Romney had captured more than 70% of the primary vote.
Opinion polls suggest Mr Romney is locked in an extremely close race with Mr Obama.
The delegates are set to officially anoint Mr Romney as the Republican nominee in late August when the party holds its national convention in Tampa, Florida.
He will become the first Mormon White House nominee, and surpass his father, George Romney, a former Michigan governor who ran unsuccessfully for the Republican nomination in 1968.
“I am honoured that Americans across the country have given their support to my candidacy and I am humbled to have won enough delegates to become the Republican Party’s 2012 presidential nominee,” Mr Romney said in statement.
As polls closed, the former Massachusetts governor was attending a fundraiser in Las Vegas with real estate tycoon Donald Trump.
He spent the day campaigning in Colorado and Nevada.
Ahead of Tuesday’s private fundraiser, the Obama campaign released a video focusing on Mr Trump’s comments falsely alleging that the president was born in Kenya.
The video seeks to draw a contrast between Mr Romney and Senator John McCain, the 2008 Republican nominee, who once corrected a woman after she called Mr Obama a Muslim.
“Why won’t Mitt Romney do the same?” asks the clip.
On Monday, Mr Romney stopped short of condemning Mr Trump’s comments.
“I don’t agree with all the people who support me. And my guess is they don’t all agree with everything I believe in,” Mr Romney told reporters.
Prominent US conservative commentator George Will waded into the row on Sunday, appearing on a political talk show where he referred to Mr Trump as a “bloviating ignoramus” and questioned the Romney campaign’s decision to appear with him.
The Obama campaign video against Mr Trump is the latest in a series of attack ads.
On Monday, the Romney campaign released an attack ad criticising Mr Obama over a federal loan to a solar panel maker which later went bankrupt.
On Tuesday Mr Romney also met casino tycoon Sheldon Adelson, who gave millions to supporters of Newt Gingrich’s campaign during the primary season.
Experts say the outcome of November’s election could depend on what happens in a handful of battleground states, including Colorado and Nevada, as the candidates vie for the support of independent voters.
The next question of the campaign is who Mr Romney will pick as his vice-presidential running mate.
Dear TNT Reader,
At The News Tribe, our mission is to bring you free, independent, and unbiased news and content that keeps you informed and empowered. We are committed to upholding the highest standards of journalism, as we understand that we are a platform for truth.
Apart from independent global news coverage, we also commit our unique focus on the Muslim world. In an age marked by the troubling rise of Islamophobia and widespread misrepresentation of Muslims in Western media, we strive to provide accurate and fair coverage.
But to continue doing so, we need your support. Even a small donation of 1$ can make a big difference. Your contribution will help us maintain the quality of our news and counteract the negative narratives that are so prevalent.
Please consider donating today to ensure we can keep delivering the news that matters. Together, we can make a positive impact on the world, and work towards a more inclusive, informed global society.
Donate Monthly Subscription Annual Subscription