(CNN) - President Donald Trump shook hands with Kim Jong Un on Sunday and took 20 steps into North Korea, making history as the first sitting US leader to set foot in the hermit kingdom.
The meeting at the Korean Demilitarized Zone -- their third in person -- came a day after Trump raised the prospect of a border handshake in a tweet and declared he'd have "no problem" stepping into the hermit nation. They shook hands inside North Korean territory before returning across the border to the South.
Kim also stepped into South Korea, describing it as a historic moment.
"I think meeting here, two countries that have a hostile past, we are showcasing to the world that we have a new present and we have a positive meeting going forward," Kim said. "Some are saying this meeting was preplanned but I was very surprised to hear about your offer on the tweet."
Shortly before the meeting, Trump proclaimed that they "understand each other."
Trump arrived to the border zone about an hour after he confirmed they were meeting and mounted an observation platform to peer into the North.
Standing alongside his South Korean counterpart, Trump appeared engaged as he listened to a US military official, who pointed at landmarks in the distance.
"It used to be very, very dangerous," Trump said, citing his briefing.
"After our first summit, the danger went away," Trump said. "When they say there's been no difference, there's been a tremendous difference."
Earlier, South Korean President Moon Jae-in -- who accompanied Trump to the heavily-guarded frontier -- said "for the first time in history the leaders of the US and North Korea will be standing face to face in Panmunjom," the border village in the DMZ.
The confirmation came after a morning of back-and-forth over whether the brief greeting would transpire after Trump on Saturday issued a public invitation for a handshake.
On Sunday morning, Trump framed the question of whether he'd actually meet Kim as a matter of logistics, indicating both sides were sorting arrangements to make the handshake happen.
"They're trying to work it out. Not so easy," Trump said, an indication the meeting's chances depended largely on whether the two sides could make the arrangements in time.
The prospect of a casual handshake between the US president and the North Korean leader along the world's most heavily fortified border would once be unthinkable. Now, the idea seems entirely in keeping with Trump's deeply personal style of diplomacy and his flair for orchestrating drama around those efforts.
Still, some diplomats even in Trump's own administration were caught off guard when he tweeted the invitation Saturday while attending the final day of the G20 summit. Trump's last meeting with Kim collapsed when the two sides could not agree on terms exchanging sanctions relief for relinquishing North Korea's nuclear arsenal. And the two sides have made little progress since.
But Trump says he's in no rush and claims to have already seen results -- both enough, in his view, for another meeting.
"If you're in a rush, you get yourself in trouble," he said during a news conference with Moon before his DMZ visit on Sunday.
He did not cast the new encounter with Kim as a breakthrough. But he said it could provide momentum to something bigger.
"It's just a step," he said. "It might be an important step and it might not."
It won't be the first attempt Trump makes to get to the DMZ, the heavily guarded stretch that has divided the Korean Peninsula for three-quarters of a century. He was foiled by weather last time around, in 2017. Always highly attuned to optics, Trump wasn't likely to pass up the opportunity to stare into the North from the observation platform.
Other presidents have made the same journey -- all peering into the hermit kingdom through binoculars -- but none have actually met the despotic leaders who rule it.
Nor has any sitting US president stepped across into the North, something Trump would not rule out on Saturday.
"Sure I would," Trump said. "I feel very comfortable doing that. I would have no problem."