President Donald Trump said efforts to curb North Korea's nuclear weapons programme would be "front and centre" of his two-day visit to South Korea and he projected optimism that the rising tensions could be calmed.
Mr Trump repeatedly addressed interlocking issues of security and trade at the heart of his visit after arriving today, saying he would be meeting with generals about North Korea.
"Ultimately it will all work out. Because it always works out. It has to work out," he said.
And later, after receiving a formal welcome from South Korean president Moon Jae-in, Mr Trump also praised Seoul's expansive purchases of American military equipment, which he said goes a long way to making the trade relationship between the two nations more equitable.
Mr Moon said he hoped Mr Trump's visit would be an opportunity to resolve "anxiety" in the region over North Korea.
"I know that you have put this issue at the top of your security agenda," Mr Moon said at the presidential residence known as the Blue House, "so I hope that your visit to Korea and to the Asia Pacific region will serve as an opportunity to relieve some of the anxiety that the Korean people have due to North Korea's provocations and also serve as a turning point in resolving the North Korean nuclear issue."
Mr Trump, in his own brief remarks, said Pyongyang would be "front and centre" of discussions but avoided the fiery language he has used so often against North Korea and its dictator, Kim Jong Un.
The president also said he had a "terrific" meeting scheduled on trade, adding, "hopefully that'll start working out and working out so that we create lots of jobs in the United States, which is one of the very important reasons I'm here".
Mr Trump, during a visit to Camp Humphreys that began his visit, sat with troops for lunch in a large mess hall.
Mr Moon was also seated at the table.
"Good food," Mr Trump told reporters as he chatted with US and Korean service members.
US and South Korean officials have said the base visit was meant to underscore the countries' ties and South Korea's commitment to contributing to its own defence.
Burden-sharing is a theme Mr Trump has stressed ever since his presidential campaign.
South Korea is the second stop on Mr Trump's five country Asian tour.
In Japan, he refused to rule out eventual military action against the north and exhorted Mr Kim to stop weapons testing, calling the recent launches of missiles over American allies like Japan "a threat to the civilised world and international peace and stability".
Mr Trump is skipping the customary trip to the demilitarised zone separating north and south, a pilgrimage made by every US president except one since Ronald Reagan as a demonstration of solidarity with the South.
A senior administration recently dubbed the border trip as "a bit of a cliche" and several other members of the administration, including Vice President Mike Pence, have visited the DMZ this year.
The White House also believes that Mr Trump has already made his support of South Korea crystal clear.
Mr Trump and Mr Moon agree on the need to pressure the North with sanctions and other deterrence measures.
However, Mr Trump has warned of unleashing "fire and fury", threatened to "totally destroy" the North, if necessary, and repeatedly insisted that all options are on the table.
Mr Moon, meanwhile, favours dialogue as the best strategy for defusing the nuclear tension and vehemently opposes a potential military clash that could cause enormous casualties in South Korea.
Mr Trump backed up his strong words about North Korea by sending a budget request to Capitol Hill on Monday for four billion US dollars to support "additional efforts to detect, defeat, and defend against any North Korean use of ballistic missiles against the United States, its deployed forces, allies, or partners".
And as he departed for South Korea, he tweeted that Mr Moon is "a fine gentleman," adding, "We will figure it all out!"
On a personal level, Mr Trump and Mr Moon have not developed the same close rapport as Mr Trump has with Japan's Shinzo Abe or even China's Xi Jinping.
Mr Trump was spending Tuesday in meetings with Mr Moon and due to hold a joint press conference and be feted at a state dinner.
Trade also is expected to be a major topic of discussion: Mr Trump has considered pulling out of the United States-Korea Free Trade Agreement, also known as Korus, blaming it for the US-South Korea trade deficit.