Sen. Rand Paul on Monday slammed Sen. John McCain for criticizing President Donald Trump during an overseas trip and called for lawmakers to stop pushing for an investigation into Trump's alleged ties with Russia.

"There's been a longstanding tradition that when you go overseas you don't toady up to sort of the socialists in Europe and you say, 'Oh they look down their nose at us and think they're better than us,'" the Kentucky Republican said on the Mike Gallagher radio show. "He goes over there and fits with that sort of theme and criticizes the president."

McCain last week told the Munich Security Conference that the Trump administration was in "disarray" after the resignation of Michael Flynn as national security adviser.

"I think that the Flynn issue obviously is something that shows that in many respects this administration is in disarray and they've got a lot of work to do," McCain said, according to a Reuters article.

"The president, I think, makes statements (and) on other occasions contradicts himself. So we've learned to watch what the president does as opposed to what he says," he said.

On calls to probe Trump's ties to Russia following media reports that his campaign aides and allies were in frequent contact with Russian intelligence officials during the presidential campaign, Paul said the effort was driven by "hysteria."

"I'd probably take a step back and you know, talk about what we're actually investigating here," Paul said.

"I wouldn't really want a special investigator if all we're hearing is gossip in the media and nobody's presented any proof that there have been connections or that any law has been broken, for that matter. So I think before people jump to sort of the hysteria of a special prosecutor, why don't we have somebody present evidence of some sort of wrongdoing before we go forward?"