MITCH McCONNELL: It's time for Donald Trump to 'put aside all the score settling' with Republicans

Senate Majority Leader Mitch McConnell on Tuesday called for a ceasefire of sorts between Donald Trump and his fellow Republicans.

During a Tuesday interview with Business Insider to promote his newly released memoir, "The Long Game," the Senate majority leader said it was time for Trump, the presumptive GOP nominee, to stop focusing on "score settling."

"Well it's pretty clear he's going to be the nominee, and I would think the better path to take would be to unify the party rather than settling grudges or old scores," he said. "I hope Trump will go in a different direction."

"He's not a dumb guy, he's a smart guy," McConnell continued. "He's earned the nomination. Now's the time to put the party together, and I would put aside all the score settling with people who competed with him for the nomination or said things."

During his last week on the campaign trail, Trump has made it abundantly clear he's not ready to put behind him past grievances with fellow Republicans. Trump took aim last week alone at Sen. Ted Cruz, 2012 Republican nominee Mitt Romney, former Florida Gov. Jeb Bush, and New Mexico Gov. Susana Martinez, among others.

"We have to get your governor to get going - she's got to do a better job, OK?" Trump said during a New Mexico rally of Martinez, who has yet to endorse him. "Your governor has got to do a better job. ... She's not doing the job. Hey, maybe I'll run for governor of New Mexico - I'll get this place going. She's not doing the job. We got to get her moving. Come on. Let's go, governor."

Republicans have taken notice at Trump's apparent refusal to drop the friendly-fire insults.

Yet during Trump's Tuesday news conference, the presumptive nominee signaled he'd continue to be harsh toward the prominent Republicans who have refused to back his candidacy.

"The real story is how fast we're getting together," Trump said. "Now, if I have a Republican that is not on my side, I'm not going to … why should I be particularly nice to that person?"

"If I have a person that's not going to support me, I have no obligation," he continued. "Politically, I might be right, I might be wrong, but that's who I am."

During his interview with Business Insider, McConnell also warned the Republicans who remain steadfastly against Trump's candidacy of the potential perils of mounting a third-party effort.

The Senate majority leader also called on Trump to release his tax returns, something the mogul has so far refused to do.