"I have been treated very unfairly," Trump added.
Trump and his team have braced for the possibility of a contested convention in recent weeks, as opposing forces have set their sights on denying him the nomination by preventing him from crossing the necessary delegate threshold.
Trump said yesterday that he believes establishment Republicans and the Republican National Committee in particular have not treated him with respect.
"I'm the frontrunner by a lot. I'm beating Ted Cruz by millions of votes," he said. "This was not going to happen with the Republican Party. People who have never voted before, Democrats and independents are pouring in and voting for me."
Cruz was asked three times by Cooper whether he would support the nominee.
"I'm not in the habit of supporting someone who attacks my wife and attacks my family," Cruz said, making reference to Trump.
When Cooper followed up, Cruz replied: "Let me tell you my solution to that: Donald is not going to be the GOP nominee."
Cooper pressed him a third time. Cruz responded: "I gave you my answer."
Kasich said he would have to "see what happens" in the race before he could answer the question.
Trump pointed to strategic manoeuvring in Louisiana that could result in Cruz capturing more delegates from the state despite the fact that Trump won the statewide vote.
"I call it bad politics. When somebody goes in and wins the election and goes in and gets less delegates than the guy that lost, I don't think that's right," he said.
"I'll see who it is," Trump added. "I'm not looking to hurt anybody. I love the Republican Party."
- Washington Post - Bloomberg