Senate Majority Leader Mitch McConnell, in some of his toughest comments to date, called out President Donald Trump on Monday for his failure to grasp how Congress works and his "excessive expectations" about getting bills passed.

McConnell offered his observations of Trump in remarks to a Rotary Group in northern Kentucky, saying that the president doesn't understand the slow-churning legislative process and has failed to stay on message to promote his agenda.

"Our new president, of course, has not been in this line of work before, and, I think, had excessive expectations about how quickly things happen in the democratic process," McConnell said, according to WLWT, an NBC-affiliate station in Cincinnati, Ohio.

"And so, part of the reason people feel like we’re under performing is because too many kind of artificial deadlines, unrelated to the reality of the complexity of legislating, may not have been fully understood," the Kentucky Republican added.

McConnell also took issue with the president's frequent tweeting, which Trump has used as a modern-day bully pulpit to praise and often condemn lawmakers.

"I’ve been, and I will be again today, not a fan of tweeting, and I’ve said that to him privately, and other events publicly," he said. "I think it would be helpful if the president was a little more on message."