Eyeing a history-making photo opportunity, President Donald Trump on today issued a Twitter invitation to North Korea's Kim Jong Un to join him for a hand shake during a visit to the demilitarized zone (DMZ)  with South Korea.

The invitation, while long rumored in diplomatic circles, still struck as an impulsive display of showmanship by a president bent on obtaining a legacy-defining nuclear accord.

Read more: SKorea ready to facilitate Trump–Kim summit: Moon

Presidential visits to the DMZ are traditionally treated as carefully guarded secrets for security reason. And White House officials couldn't immediately say whether Kim had agreed to meet with Trump. The president himself claimed he wasn't even sure Kim was in North Korea to accept the invitation.

"All I did is put out a feeler, if you'd like to meet," Trump said later of the message to Kim. He added, somewhat implausibly, that "I just thought of it this morning."

Trump is scheduled to fly to South Korea later today after he concludes meetings at the Group of 20 summit in Osaka, Japan, including with the president of China. He told reporters during a breakfast with Saudi Arabian Crown Prince Mohammed bin Salman that he would be visiting the heavily fortified area between the two Koreas.

"We're going there," the president said.

Shortly before the breakfast, Trump tweeted his invitation for Kim to meet him there. "If Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!" he wrote.

It was not immediately clear what the agenda, if any, would be for the potential third Trump-Kim meeting. Trump predicted that, "If he's there we'll see each other for two minutes." Still, such a spectacle would present a valuable propaganda victory for Kim, who, with his family, has long been denied the recognition they sought on the international stage.

Despite Trump's comments Saturday, he had told The Hill newspaper in an interview this week that he would be visiting the DMZ and said "he might" meet with Kim. The paper reported it had withheld Trump's comments, citing security concerns by the White House.

North Korea's state media made no mention today of a possible meeting between Trump and Kim. South Korea's presidential Blue House said in a tweet that Trump asked South Korean President Moon Jae-in at the G20 meetings whether he'd seen Trump's Twitter message to Kim. When Moon replied he had, Trump said "(Let's) try doing it" and raised his thumb, the Blue House said.

Trump's summit with Kim in Vietnam earlier this year collapsed without an agreement for denuclearizing the Korean Peninsula. He became the first sitting US president to meet with the leader of the isolated nation last year in Singapore, where they signed a broad agreement to bring the North toward denuclearization.

Substantive talks between the two nations have largely broken down since then, as the North has balked at Trump's insistence that it give up its weapons before it sees relief from crushing international sanctions.

Still, Trump has sought to publicly heap praise on Kim, who oversees an authoritarian government, in hopes of keeping the prospects of a deal alive, and the two have traded flowery letters in recent weeks.

Every president since Ronald Reagan has visited the 1953 armistice line, except for George HW Bush, who visited when he was vice president. The show of bravado and support for South Korea, one of America's closest military allies, has evolved over the years to include binoculars and bomber jackets.

Trump, ever the showman, appears to be looking to one-up his predecessors with a meeting with Kim.

As he left the White House for Asia earlier this week, Trump was asked whether he'd meet with Kim while he is in the region.

 "I'll be meeting with a lot of other people ... but I may be speaking to him in a different form," Trump said.

Such trips to the demilitarized zone, the heavily fortified border between North and South Korea, are usually undertaken under heavy security and the utmost secrecy. Trump tried to visit the DMZ when he was in Seoul in November 2017, but his helicopter was grounded by heavy fog.

Trump has staked his self-professed deal-making reputation on his rapprochement with the North and has even turned it into a campaign rallying cry. Trump has repeatedly alleged that if he had lost the 2016 presidential campaign, the US would be "at war" with North Korea over its nuclear weapons and ballistic missile programs.

The meeting would come at a time of escalating tensions. While North Korea has not recently tested a long-range missile that could reach the US, it last month a fired off a series of short-range missiles. Trump has brushed off the significance of the tests, even as his own national security adviser, John Bolton, has said they violated UN Security Council resolutions.

Trump also suggested Saturday that the North was prepared to turn over additional unidentified remains of unknown American and allied service-members. At least six Americans have been identified from 55 boxes of remains delivered by the North last year after Trump's first meeting with Kim, but the Defense Department in May announced it was halting efforts to recover additional remains, citing a lack of cooperation from North Korea.