Though he refrained from naming names, Prime Minister Justin Trudeau strongly hinted that an undercurrent of anger, fear and frustration appears to be driving many American voters to back Republican front-runner Donald Trump, in the run-up to the U.S. election.

The PM told a business crowd in Washington, D.C. on Thursday that he is "hopeful" the anti-establishment attitude of many Americans will bring about positive change in democracy. However, he also cautioned against taking a "this is as good as it gets" approach, saying that voters should cast their ballots for a future they can be confident and excited about.

"I think we're seeing a frustration against political systems and political establishments that is coming out, and, quite frankly, scaring a few people in the establishment," Trudeau said during a Q&A session at the U.S. Chamber of Commerce.

Neither Trudeau nor the Q&A moderator mentioned Trump by name as they indirectly referred to his campaign several times.

"There's a lot of people wondering how the U.S. got to the particular point they're at this particular week," Trudeau said, as he spoke of a growing sense of "nihilism" in some parts of society. He also suggested that "polarization, anger, anxiety and frustration" can lead to "everything from poor electoral choices to challenges in global security issues."

The PM added that, with the U.S. election fast-approaching, he has "tremendous confidence in what Abraham Lincoln referred to as the better angels of our nature."

With speculation already swirling about how Trudeau might get along with a possible President Trump, one high-profile Republican suggested the two could work together despite the "natural friction" caused by their ideologies.

Trump supporter Newt Gingrich, a former GOP presidential candidate in 2012, said Trudeau and Trump would be able to get over their differences "issue by issue," in the event Trump becomes president.

"I think that Trump is a very practical person and he does business in Canada, knows Canada reasonably well, and I think that his inclination will be to go issue by issue," Gingrich told the Canadian Press.

Gingrich also suggested Trump would be more supportive of the Keystone XL pipeline, a project that current U.S. President Barack Obama rejected in November.

Trudeau is scheduled to attend a working lunch with Japanese Prime Minister Shinzo Abe, before attending a nuclear summit at the White House, hosted by U.S. President Barack Obama. The two-day meeting will continue on Friday with a discussion about the worst-case scenario of terrorists obtaining a nuclear weapon.

With files from The Canadian Press