US President Barack Obama. REUTERS/Kevin Lamarque US President Barack Obama harshly criticized the entire slate of Republican presidential candidates during a press conference on Tuesday afternoon.

"I think foreign observers are troubled by some of the rhetoric that's been taking place in these Republican primaries and Republican debates," Obama said when asked what foreign leaders thought of Donald Trump.

Obama emphasized that his comments were not directed solely at Trump, the Republican presidential front-runner.

The president listed multiple issues, including climate change and immigration, on which he thought all of the GOP candidates were out of step:

I find it interesting that everybody's focused on Trump primarily just because he says in more interesting ways what the other candidates are saying as well. So he may up the ante in anti-Muslim sentiment, but if you look at what the other Republican candidates have said, that's pretty troubling, too. He may express strong anti-immigration sentiment, but you've heard that from the other candidates as well. ...

They're all denying climate change. I think that's troubling to the international community, since the science is unequivocal. And, you know, the other countries in the world, they kind of count on the United States being on the side of science and reason and common sense. ... But this is not just Mr. Trump. Look at the other statements that are being made by the other candidates.

By linking Trump's provocative statements and policies to the other GOP candidates, Obama echoed the Democratic Party's broader messaging.

But it was clear from the press conference that Obama viewed Trump with particular disdain. He predicted that Trump would not win the 2016 presidential race because the American electorate is too sober to place him in such an important position.

"I continue to believe Mr. Trump will not be president. And the reason is because I have a lot of faith in the American people. And I think that they recognize that being president is a serious job," Obama said.

"It's not hosting a talk show or a reality show," he added. "It's not promotion. It's not marketing. It's hard. And a lot of people count on us getting it right. And it's not a matter of pandering and doing whatever will get you in the news on a given day."

At a rally on Tuesday evening, Trump fired back, saying that Obama was "lucky" the reality-television star didn't run for president in 2012.

"This man has done such a bad job, he has set us back so far. For him to say that is a great compliment, to tell you the truth," Trump said. "You're lucky I didn't run last time when Romney ran, because you would've been a one-term president."

Maxwell Tani contributed reporting.