Donald Trump, a former reality television star, has never held public office. His win in Indiana made him the presumptive presidential nominee, averting the possibility of a contested convention.
Donald Trump's last remaining challenger for the Republican Party presidential nomination, John Kasich, dropped out of the race on Wednesday, US Media reported, leaving the presumptive nominee with the task of uniting a fractured party around his White House bid.
Ohio Governor Kasich, who had stubbornly persisted with his campaign despite never having a viable path to the nomination, canceled a media appearance on Wednesday in Virginia and scheduled a 5 pm EDT (2100 GMT) statement in Columbus, Ohio, his campaign said.
Media reports said he would suspend his campaign. Kasich's campaign did not immediately respond to Reuters' request for comment.
Kasich's departure will clear the field for Trump after the real estate mogul's chief rival, US Senator Ted Cruz, ended his campaign on Tuesday following his defeat in Indiana's Republican primary contest.
But Trump faces persistent opposition from some party loyalists who fear his positions on key issues could set up Republicans for massive losses to the Democrats in the November 8 election.
Trump, a former reality television star, has never held public office. His win in Indiana made him the presumptive presidential nominee, averting the possibility of a contested convention when Republicans choose their nominee at their gathering in Cleveland July 18-21.
Trump's win cleared the way him to prepare for a likely match-up in the November 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 have been 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."