McConnell made the comments in a podcast
with Bloomberg Politics, as he continued to repudiate comments made by Trump about a federal judge
"He needs someone highly experienced and very knowledgeable because it's pretty obvious he doesn't know a lot about the issues," McConnell said of a running mate for the mogul.
McConnell said the obvious lack of knowledge is another reason that the Kentucky Republican has pressed the presumptive GOP nominee to use scripts.
"You see that in the debates in which he's participated," McConnell said. "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 comments were the latest in a string of criticism of Trump from McConnell, who has called Trump's comments about the judge "totally inappropriate."
Trump has faced a firestorm since saying the Indiana-born judge in his Trump University lawsuit may be biased because he has Mexican heritage. While most of the top members of the Republican Party have called out the comments
, they are also sticking by their endorsements of Trump.
McConnell stood by that, but said Trump needs to show improvement.
"I object to a whole series of things that he's said -- vehemently object to them. I think all of that needs to stop. Both the shots at people he defeated in the primary and these attacks on various ethnic groups in the country," McConnell told Bloomberg.
And McConnell wouldn't flatly rule out rescinding his endorsement, dodging the question when asked directly.
"I'm not going to speculate about what he might say, or what I might do," he 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."