Ohio Governor John Kasich has ended his campaign for the US Republican presidential nomination.
Mr Kasich's departure leaves Donald Trump standing alone to claim the Republican mantle at the party's convention in July.
Making the announcement to supporters in Ohio, Mr Kasich said: "As I suspend my campaign today, I have renewed faith - deeper faith - that the Lord will show me the way forward".
In a post on his website, Mr Kasich said: "Together, we fought the good fight and did it the right way".
"Your devotion to our campaign based on our shared belief in solving our nation's challenges by uniting people and lifting them up will forever remain in the hearts of my family and me".
"From the bottom of my heart, thank you", he added.
This picture of John Kasich and his family was posted on his website | Image: johnkasich.com
The billionaire Mr Trump was declared the GOP's presumptive nominee on Tuesday after a resounding primary victory in Indiana that prompted his closest rival Ted Cruz to suspend his campaign.
Over the past seven months, Mr Trump has slowly seen more than a dozen of his Republican rivals step aside.
Rick Perry was first to bow out last September followed by Scott Walker, Bobby Jindal, Lindsey Graham, George Pataki, Mike Huckabee, Rand Paul, Rick Santorum, Carly Fiorina, Chris Christie, Jim Gilmore, Jeb Bush, Ben Carson, Marco Rubio and Mr Cruz.
Even as the field dwindled, Mr Kasich struggled to connect with Republican voters during the often contentious campaign.
The 63-year-old former congressman managed just one primary win in his home state of Ohio, but the lack of victories did not deter him for staying in the race despite growing calls for him to quit.
Mr Kasich painted himself as the only Republican candidate who could defeat Hillary Clinton in an election, and set his sights on a contested convention, where he hoped to surpass Mr Trump at the last moment.
But an unlikely alliance with Mr Cruz, in which the two sought to slow the property mogul's momentum, failed to yield results for either candidate.
Mr Kasich managed just 153 delegates, putting him fourth overall behind Mr Trump, Mr Cruz and Mr Rubio, who left the race in mid-March.
Some 1,237 delegates are needed to secure the Republican nomination.
Mr Trump has pocketed 1,047 delegates so far, with several states to go before the party's convention in Cleveland.
