Trump discloses new details on North Korea summit, defends his 'bigger button' tweet

President Donald Trump offered new insights into his administration's preparations for a summit with North Korean dictator Kim Jong Un as he defended his bellicose approach and "bigger button" tweet, saying only a "weak" leader would get the U.S. into nuclear war.

The details came just hours before South Korean President Moon Jae-in is set to meet Kim for a historic one-on-one meeting, but with Trump again casting doubt on his own summit next month or in early June.

"It could be that I walk out quickly –- with respect, but it could be. It could be that maybe the meeting doesn’t even take place. Who knows?" Trump told Fox News's "Fox and Friends."

The two sides have narrowed down possible locations to five, according to Trump, with three or four dates in the running. One senior U.S. official previously told ABC News that Trump had ruled out China and that it was highly unlikely Kim would agree to meet in the U.S. or Trump to meet in North Korea.

Possible venues include Europe – like Switzerland, where Kim went to university, and Sweden, the U.S.'s protecting power in North Korea -- South Asia, and the demilitarized zone between North and South Korea, where Moon and Kim are set to meet Friday.

Trump also revealed more about the secret visit by then-CIA director Mike Pompeo – just confirmed as secretary of state – made to Pyongyang. Pompeo was not scheduled to meet with Kim, Trump said, but the North Koreans arranged it after he arrived.

"We have incredible pictures of the two talking and meeting, which I'd love to release if we can. I'll do that actually. It's not a bad idea," Trump said.

Hours later, White House Press Secretary Sarah Sanders tweeted two photos of the men shaking hands.

Pompeo also met with his North Korean "counterparts," Trump added, presumably in intelligence agencies. But his encounter with Kim lasted more than an hour, Trump said, and "they got along."

On Wednesday, Trump was criticized for his warm words for the strongman -- accused of starvation, torture, and brutal repression -- calling him "very open" and "very honorable."

Trump reiterated his approval Thursday, commending North Korea because, "They’ve given up denuclearization, testing, research – we’re going to close different sites."

But it's unclear if North Korea has really agreed to those things – or whether they've done so in good faith. The country announced on April 21 that it will stop nuclear tests and launches of intercontinental ballistic missiles and close its nuclear test site Punggye-ri, where it had conducted its six nuclear tests, including its largest last September that purportedly was a hydrogen bomb.

Whether that was a sign of them giving in, as Trump argued, is debatable. On state-run Korean Central News Agency, Kim was quoted as saying, "Under the proven condition of complete nuclear weapons, we no longer need any nuclear tests, mid-range and intercontinental ballistic rocket tests, and that the nuclear test site in the northern area has also completed its mission."

In other words, the North had already achieved its goal of nuclear weapons, so it no longer needed testing or this facility. It also has yet to publicly say it has agreed to denuclearization – what Trump defined as "they get rid of their nukes."

Instead, the world has heard through intermediaries that North Korea has "expressed its commitment to denuclearization," as South Korea's Moon put it last week, or that it is North Korea's "consistent stand to be committed to denuclearization on the peninsula," as official Chinese news service Xinhua reported in March.

Either way, those are not the same thing as getting "rid of their nukes."

But Trump doubled down on Fox, saying, "We haven't even really that much asked him [to give things up] because we would've asked him, but they gave it up before I even asked."

The president attributed that success to his own combative rhetoric.

"It was very, very nasty, you know, with 'Little Rocket Man' and with the buttons and my button's bigger," Trump said. "Everybody said this guy is going to get us into nuclear war."

But it would be a "weak" leader that would get the U.S. into a nuclear war, he argued, and instead talks are moving forward.

"Now they're saying, 'Wow, it looks like that will be taken care of.' I think we're doing very well. Let's see what happens," he said.