Donald Trump has suggested he could "make a deal" with Kim Jong Un over his nuclear programme – after weeks of threats to destroy North Korea.
On his first day on the Korean peninsula, the President said the US would use military force if needed – but toned down his rhetoric, predicting that "ultimately, it'll all work out".
During a news conference alongside South Korean President Moon Jae-in, Mr Trump said he had seen "a lot of progress" on the North Korea issue.
He said: "It makes sense for North Korea to come to the table and make a deal that is good for the people of North Korea and for the world."
The President underlined America's military strength in the region, noting that three aircraft carrier groups and a nuclear submarine had been deployed there.
But he said: "We hope to God we never have to use" military options.
Mr Trump is on a tour of Asia that will take him and first lady Melania to five countries over 11 days.
He has previously threatened to unleash "fire and fury" on North Korea and sought to belittle the country's leader by calling him "Little Rocket Man".
He said Mr Kim is threatening "millions and milions of lives, so needlessly" and that one of the main goals of his Asia trip was to secure help from countries like China and Russia to pressure Pyongyang into giving up its nuclear ambitions.
Sky's Asia Correspondent Katie Stallard said: "Now that he is actually here on the Korean peninsula, Donald Trump's public comments have been notably more restrained.
"This is quite a departure from his statement just weeks ago that negotiations were a waste of time.
"After meeting senior military officers earlier, he said that it would 'all work out, like it always works out, it has to work out'.
"But of course, historically here, it has not always worked out."
Mr Moon said the two leaders had "agreed to resolve the North Korea nuclear issue in peaceful manner" that would "bring permanent peace" to the peninsula.
Mr Trump praised South Korea for buying US military equipment and said he hoped to improve on the two countries' current trade agreement, which he said was "not successful and not very good" for the United States.
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.