(CNN) US President Donald Trump said on Monday he'd be "honored" to meet with North Korean dictator Kim Jong Un , clarifying he meant "under the right circumstances."

That came just 48 hours after he invited Philippines leader Rodrigo Duterte to the White House , surprising the State Department and breaking with long-held tradition. Duterte has since said he might be too busy for any visit to Washington soon.

These are just the two latest signs of Trump's openness to, or perhaps fascination with, the world's strongmen.

Here's some of what he's said about other iron-fisted world leaders:

Xi Jinping: 'He is a terrific person'

JUST WATCHED Trump: Soften my stance on China? Who, me? Replay More Videos ... MUST WATCH Trump: Soften my stance on China? Who, me? 01:10

As candidate, Donald Trump often described China as the enemy -- accusing it of manipulating currency and effectively stealing manufacturing jobs. But as President, he found he liked his Chinese counterpart quite a lot and said they developed a "very good relationship" as a meeting planned for 15 minutes stretched and stretched.

"I think he is a terrific person. I really got to know him very well over a two-day period. we were together hours and hours and hours by ourselves. We had a 15-minute scheduled meeting and it lasted for three hours. The same thing happened the next day. We have a good chemistry together."

The friendly tone toward Xi also speaks to Trump's new priorities: "What, am I going to start a trade war with China in the middle of him working on a bigger problem with North Korea?" he asked during a "Fox and Friends" interview

Kim Jong Un: 'A smart cookie'

JUST WATCHED Trump on Kim Replay More Videos ... MUST WATCH Trump on Kim 02:45

The Trump administration has adopted a harder line with Pyongyang as tensions between the two countries have continued to escalate in recent weeks. Despite this, the President expressed admiration for how Kim Jong Un handled ascending to power at such a young age in an interview with Reuters on April 28.

"He's 27 years old. His father dies, took over a regime. So say what you want but that is not easy, especially at that age," Trump said. "I'm not giving him credit or not giving him credit, I'm just saying that's a very hard thing to do. As to whether or not he's rational, I have no opinion on it. I hope he's rational."

Just a day later, Trump expanded on his assessment of Kim in an interview with CBS's "Face the Nation," saying: "He's a pretty smart cookie... But we have a situation that we just cannot let -- we cannot let what's been going on for a long period of years continue."

And on Monday, he said to Bloomberg News : "If it would be appropriate for me to meet with him, I would absolutely, I would be honored to do it. If it's under the, again, under the right circumstances. But I would do that."

Recep Tayyip Erdogan: Kudos for coup response

Trump appeared to offer his seal of approval for Erdogan's ambitions to replace Turkey's current system of parliamentary democracy with an all-powerful executive presidency in a congratulatory phone conversation shortly after the Turkish referendum

While many have criticized Erdogan's crackdown on major opposition figures, a senior Trump administration official told CNN that the call bypassed the subject and instead focused mostly on Syria.

Prior to this, Trump had previously shown admiration for how Erdogan had handled the last year's failed coup in a July 2016 interview with the New York Times

"I give him great credit for being able to turn that around," he said.

Abdel Fattah el-Sisi: A 'fantastic guy'

JUST WATCHED Trump: I hope you like me better Replay More Videos ... MUST WATCH Trump: I hope you like me better 00:47

Trump heaped praise on Egyptian President Abdel Fattah el-Sisi during his April visit to the White House.

The visit was designed to signal a shift in US-Egyptian relations following a cooler period during the Obama administration. And Sisi, a former general, is the kind of strongman leader Trump admires.

Trump praised the Egyptian leader as "fantastic guy," declaring that his "tough approach" had "gotten the terrorists out (of Egypt)."

Vladimir Putin: 'Better than Obama'

JUST WATCHED Trump on Putin: One tough cookie Replay More Videos ... MUST WATCH Trump on Putin: One tough cookie 01:48

Long before he took office, Trump was fawning over the Russian leader.

"I've always had a good instinct about Putin," Trump said in December 2015 interview with Iowa radio host Simon Conway, years before the two would meet.

In a September 2016 interview with NBC's Matt Lauer, the then-presidential nominee continued to shower Putin with admiration, calling him a stronger leader than Barack Obama.

"I've already said, he is really very much of a leader. I mean, you can say, 'Oh, isn't that a terrible thing' -- the man has very strong control over a country," Trump said . "Now, it's a very different system, and I don't happen to like the system. But certainly, in that system, he's been a leader, far more than our president has been a leader."

And since assuming the presidency, Trump has tweeted Putin's criticism of Hillary Clinton and chastised her for speaking badly of him. He even went as far as defending the Russian leader to Fox News' Bill O'Reilly, who called Putin a killer in an interview.

"There are a lot of killers," Trump said on February 6, 2017. "Do you think our country is so innocent? Do you think our country is so innocent?"