U.S. President Donald Trump and North Korean leader Kim Jong Un cross over a military demarcation line at the demilitarized zone (DMZ) separating the two Koreas, in Panmunjom, South Korea, June 30, 2019. It was the third meeting between the two leaders in just over a year and will raise hopes for a revival of stalled nuclear talks. KCNA via REUTERS

U.S. President Donald Trump shakes hands with North Korean leader Kim Jong Un as they meet at the demilitarized zone separating the two Koreas, in Panmunjom, South Korea, June 30, 2019. KCNA via REUTERS

U.S. President Donald Trump meets with North Korean leader Kim Jong Un at the demilitarized zone separating the two Koreas, in Panmunjom, South Korea, June 30, 2019. REUTERS/Kevin Lamarque

U.S. President Donald Trump and North Korean leader Kim Jong Un stand at the demarcation line in the demilitarized zone separating the two Koreas, in Panmunjom, South Korea, June 30, 2019. REUTERS/Kevin Lamarque

U.S. President Donald Trump meets with North Korean leader Kim Jong Un at the demilitarized zone separating the two Koreas, in Panmunjom, South Korea, June 30, 2019. REUTERS/Kevin Lamarque

U.S. President Donald Trump meets with North Korean leader Kim Jong Un at the demilitarized zone separating the two Koreas, in Panmunjom, South Korea, June 30, 2019. REUTERS/Kevin Lamarque