Mitch McConnell. AP Photo/Evan Vucci Mitch McConnell made some of his strongest statements yet relating to Donald Trump in an interview published Friday by Bloomberg.

The Senate majority leader told the outlet that he had privately pleaded with Trump to start reading scripts because "it's obvious he doesn't know a lot about the issues."

McConnell added that Trump needs a "highly experienced" running mate as a result.

"He needs someone highly experienced and very knowledgeable because it's pretty obvious he doesn't know a lot about the issues," McConnell said on Bloomberg's "Masters in Politics" podcast. "You see that in the debates in which he's participated. It's why I have argued to him publicly and privately that he ought to use a script more often — there is nothing wrong with having prepared texts."

The Kentucky Republican also wouldn't take rescinding his endorsement of Trump off the table after what has been a chaotic week in the Manhattan billionaire's campaign.

"I'm not going to speculate about what he might say or what I might do," McConnell said. "But I think it's pretty clear, and I've been pretty clear publicly about how I think he ought to change direction, and I hope that's what we are going to see."

In an interview with Business Insider last week as a part of a promotional tour he's on to peg his newly released memoir, "The Long Game," McConnell said it's time for Trump to stop "score settling" with those who opposed him during the primary season.

"I think he'd have a much better chance of winning if he would quit making so many unfortunate public utterances and stick to the script,” he told Bloomberg.

McConnell said he even pressed Trump in person to become more scripted. He brought that message before Trump at the recent National Rifle Association convention in Louisville, Kentucky.

Donald Trump. AP Photo/Jae C. Hong

"I said, ‘Hey, Donald, you got a script?’ and he pulled it out of his pocket," McConnell said. "He said, 'You know I hate scripts. They're so boring.' And I said, 'Put me down in favor of boring.'"

He continued his retelling of the conversation with Trump:

'You've demonstrated that you have a lot of Twitter followers and you're good at turning on a big audience. Now you need to demonstrate you have the seriousness of purpose that is required to be president of the United States, and most candidates on frequent occasions use a script.' So we'll see whether that's something he's capable of doing.

McConnell's statements come as Trump has been caught up in his latest self-inflicted firestorm — this time relating to attacks he has launched at a federal judge over his Mexican heritage.

The Manhattan billionaire said that US District Court Judge Gonzalo Curiel cannot fairly preside over a civil case involving Trump University, his now defunct for-profit real estate school, because he is of Mexican descent and Trump will be "building a wall" along the US-Mexico border if elected in the fall.

Curiel is from Indiana.

Republicans from all sides of the party — including McConnell, previously — have publicly condemned the remarks and demanded that Trump change his tone. In a Tuesday afternoon statement, Trump took a step back from the attacks but did not apologize. He made no mention of his attacks against the judge in his scripted postprimary speech later that night.

The blowback from the attacks may have been evident in a Thursday Fox News poll, which found that Trump had dipped six percentage points since last month in a head-to-head with Hillary Clinton — including dropping a whopping 11 points with independent voters.

McConnell told Bloomberg that the election will be unwinnable if Trump continues to attach his hopes solely to the white male vote.

"We are not going to be competitive in presidential elections appealing only to white voters and particularly writing off white women," he said. "So beyond the unfortunate part of the various things that our nominee has said — it's not smart, politically."