Indianapolis: Billionaire Donald Trump assumed the mantle of presumptive Republican presidential nominee on Wednesday with a message on unity that also suggested he was not going to work too hard to placate some party establishment figures angered by his outsider candidacy.
The former reality television star, who has never held public office, won a commanding victory in Indiana's primary on Tuesday, forcing his main rival, US Senator Ted Cruz, to drop out of the race.
Trump's win cleared the way him to prepare for a likely match-up in the November 8 general election against former Secretary of State Hillary Clinton. Democratic front-runner Clinton lost the Indiana primary to her tenacious challenger, US Senator Bernie Sanders, but remains on course to become her party's nominee.
The New York businessman's immediate challenge is to mend deep fissures within the Republican Party, easing tensions with party loyalists who are appalled by his bombastic, bullying style, his denigrating comments about women and his proposals to build a wall on the border with Mexico and deport 11 million illegal immigrants.
But in a series of Wednesday morning television interviews, Trump, 69, made clear he would not forget some wounds from a tumultuous primary campaign in which many establishment Republicans rejected him and spawned Stop Trump and Never Trump movements.
"I am confident that I can unite much of it, some of it I don't want," Trump said on NBC's "Today" show. "Honestly, there are some people I really don't want. People will be voting for me. They're not voting for the party."
Since launching his White House bid last summer as a longshot amid a crowded field that included governors, former governors and US senators, the real estate magnate repeatedly defied predictions that his campaign would implode.
He prevailed over rivals he derided as "grown politicians," despite making provocative statements along the way that drew sometimes furious criticism from many in the party but fed his anti-establishment appeal.
Trump also directed fire at Clinton, telling MSNBC, "She is a disaster, and she will be a disaster as president."
With his nomination all but assured, Trump is looking for a running mate. He said on ABC he would choose a Republican, most likely an elected official with political experience. "I'm considering a lot of people," Trump told Fox News.
Trump's victory in Indiana and Cruz's withdrawal means he now looks to have a clear path to be formally nominated as the Republican candidate at the party convention in July, rather than battling for the prize at a contested convention. Nonetheless, Ohio Governor John Kasich vowed to stay in the race until California holds its primary on June 7.
Republican National Committee Chairman Reince Priebus called Trump the party's presumptive nominee in a tweet and said, "We all need to unite and focus" on defeating Clinton.
In an interview Wednesday, Priebus acknowledged achieving Republican unity would be difficult. "It's going to take some time but we're going to get there," he said on CNN.
Bill Kristol, the neoconservative editor of the Weekly Standard, said on Twitter, "The battle for the 2016 GOP nomination is over. The battle for the soul of the Republican Party (or its successor) has just begun."
Support for Trump among Republicans nationally jumped in recent weeks to the highest level of the primary campaign, according to Reuters/Ipsos polling. A recent poll found Trump with the support of 53 per cent of Republican participants, well above Cruz at 25 per cent. Kasich had 16 per cent.
In a potential general election match-up, however, Clinton led Trump by about 10 percentage points among likely voters. The poll included 623 Democrats and 556 Republicans and had a credibility interval of 5 percentage points.
As the primary returns flowed, Cruz announced he had ended his campaign in Indianapolis. The senator from Texas, 45, sounding beaten but defiant, said he no longer saw a viable path to the nomination.
"We gave it everything we got. But the voters chose another path, and so with a heavy heart, but with boundless optimism for the long-term future of our nation, we are suspending our campaign," said Cruz, who is from the party's conservative Tea Party movement.
Cruz's exit came as a surprise, and many Republicans who had denounced Trump were grappling with what to do next.
Reuters/Ipsos polling in April found Cruz supporters split on whom to support if their candidate quit.
Lanhee Chen, who had advised former Republican candidate Marco Rubio, on Tuesday night floated the possibility of a third-party candidate.
"Tonight's outcome raises seriousness & urgency of discussions about third-party alternative; how real it is depends on who steps up to run," he tweeted.
Other prominent Republicans said they would support Trump. "It's binary now. It's Trump or Clinton, my vote's for Trump," former Louisiana Governor Bobby Jindal, who dropped his own White House bid in November, said on Fox News.