Sen. Pat Toomey argued Friday that Republican presidential nominee Donald Trump should stop talking about campaign issues that don't pertain to Hillary Clinton, categorizing everything else as "unrelated discussions."

Toomey, who's engaged in an intense re-election battle himself, said on a conference call Friday morning that Trump should focus specifically on Clinton's record during her tenure at the State Department, including her involvement in Libya and Syria. He added that it would be smart for Trump to "make this case" rather than discussing other issues.

"Well, I do think that Hillary Clinton was a disaster as secretary of state. I think the policies she's supported from Libya to Syria to Russia have left America less secure, more endangered, and that's exactly the case that should be prosecuted against her," Toomey told reporters. "In my view, it would be good for Donald Trump's campaign to make this case against Hillary Clinton than getting in other unrelated discussions."

The Pennsylvania Republican added his stance remains unchanged regarding Trump, saying that he is "still watching and waiting and evaluating," keeping distance between him and the real estate mogul. After Trump became the party's presumptive nominee, Toomey wrote in an op-ed that he "was not pleased" with the presidential options before him, adding that Trump's campaign is "highly problematic."

However, Toomey continued to press that Pennsylvania voters will look independently on the presidential and senatorial contests, arguing that Trump is in "a category unto himself." He made the remark when asked about recent polls showing Trump to be trailing by double digits and how it could affect his contest.

"Honestly this far out, polling is notoriously unreliable," Toomey said. "Pennsylvania voters are really quite sophisticated and they know for sure that Donald Trump is a category unto himself. So they will make their decisions about the presidential race, and then they will make a completely separate decision about the person they want representing themselves in the United States Senate.

"I'm going to continue to run my race and underscore the very stark contrast between myself and Katie McGinty, who's in lockstep with Hillary Clinton on everything, and I think that's what Pennsylvania voters will decide," Toomey added.

At the moment, Toomey is locked in a dead heat with McGinty, the Democratic nominee. According to the latest RealClearPolitics average, the two are tied with 41.8 percent support with three months until election day.

Toomey downplayed the possibility of Republicans dumping Trump in favor of another candidate, saying that is "unlikely."