Donald Trump all but certain to face Hillary Clinton in US election
Once dismissed as a fringe contender, Donald Trump now is all but certain to lead the Republican Party into the US presidential campaign against Democratic front-runner Hillary Clinton - a stunning political triumph for a first-time candidate whose appeal to frustrated voters was widely underestimated.
The billionaire's victory in Indiana and main rival Ted Cruz's abrupt decision to drop out resolved the Republican nomination for 2016 - but still leaves the party in a deep state of uncertainty.
Some Republican leaders remain acutely wary of the bombastic businessman and have insisted they could never support him, even in a face-off against Mrs Clinton.
Nebraska senator Ben Sasse, who has consistently said he could not support Mr Trump, wrote on Twitter that he was being asked if the Indiana results changed his views.
"The answer is simple: No," Mr Sasse wrote.
Republicans such as Mr Sasse worry both about Mr Trump's views on immigration and foreign policy and his over-the-top persona.
Hours before clinching victory in Indiana, Mr Trump floated an unsubstantiated claim that Mr Cruz's father appeared in a 1963 photograph with John F Kennedy's assassin, Lee Harvey Oswald - citing a report first published by the National Enquirer.
Donald Trump still needs about 200 delegates to formally secure the nomination, but Mr Cruz's decision to end his campaign removed his last major obstacle.
Mr Trump said of his rival: "Ted Cruz - I don't know if he likes me or he doesn't like me - but he is one hell of a competitor."
Mr Trump previously dubbed him "lyin' Ted".
The billionaire, in a victory speech that was much lower-key than usual, promised victory in November, vowing anew to put "America first".
The campaign of governor John Kasich, who has won only in his home state of Ohio, said in a Facebook post: "Tonight's results are not going to alter Gov Kasich's campaign plans.
"Our strategy has been and continues to be one that involves winning the nomination at an open convention."
Mr Kasich trails Donald Trump by nearly 900 delegates.
Vermont senator Bernie Sanders eked out a victory over Mrs Clinton in Indiana, but the outcome will not slow the former secretary of state's march to the Democratic nomination.
Heading into Tuesday's vote, Mrs Clinton had 92% of the delegates she needs.
Mr Sanders was defiant, saying: "I know that the Clinton campaign thinks this campaign is over. They're wrong."
But Mrs Clinton has already has turned her attention to the general election in the autumn and a straight fight with Donald Trump.
The pair face a six-month battle for the presidency, with the future of America's immigration laws, health care system and military posture around the world at stake.
While Mrs Clinton heads into the poll with significant advantages among minority voters and women, Democrats have vowed to not underestimate Mr Trump in the same way as his Republican rivals did for too long.
Republican National Committee chairman Reince Priebus declared the GOP race over, saying on Twitter that Trump would be the party's presumptive nominee.
"We all need to unite and focus on defeating @HillaryClinton," he wrote.
However, even before the Indiana results were finalised, some conservative leaders in the Republican party were planning a meeting to assess the viability of launching a third party candidacy to compete with him in the fall.
Indiana was viewed as the last gasp for Ted Cruz, the fiery Texas conservative. He campaigned aggressively in the state, securing the support of Indiana's governor and announcing businesswoman Carly Fiorina as his running mate but lost momentum in the closing days.
Mr Cruz had clung to the hope that he could keep Trump from reaching the 1,237 delegates needed for the nomination and push the race to a rare contested convention. But aides said he made the decision to drop out early on Tuesday evening, shortly after most polls in Indiana had closed.
Mr Cruz told supporters in Indianapolis: "I've said I would continue on as long as there was a viable path to victory; tonight I'm sorry to say it appears that path has been foreclosed."
Mrs Clinton, too, needs to win over Bernie Sanders' enthusiastic supporters. The Vermont senator has cultivated a deeply loyal following, particularly among young people, whom Democrats count on in the general election.
Mr Sanders picked up at least 43 of Indiana's 83 delegates. Mrs Clinton now has 2,202 delegates to her rival's 1,400. That includes pledged delegates from primaries and caucuses, as well as superdelegates.
Mr Trump now has at least 1,047 delegates. Mr Cruz has left the stage with 565, while Mr Kasich trails with 152.