In this photo taken on June 30, 2019, US President Donald Trump shakes hands with Democratic People's Republic of Korea (DPRK) leader Kim Jong-un at the border village of Panmunjom in the Demilitarized zone. (SUSAN WALSH / AP)

US President Donald Trump steps into the northern side of the Military Demarcation Line that divides Democratic People's Republic of Korea and Republic of Korea (ROK), as DPRK's leader Kim Jong-un looks on, in the Joint Security Area of Panmunjom in the Demilitarized zone on June 30, 2019. (BRENDAN SMIALOWSKI / AFP)

DPRK's leader Kim Jong-un shakes hands with US President Donald Trump north of the Military Demarcation Line that divides DPRK and ROK. (BRENDAN SMIALOWSKI / AFP)

In this photo taken on June 30, 2019, US President Donald Trump meets with DPRK's leader Kim Jong-un at the border village of Panmunjom in the Demilitarized Zone. (SUSAN WALSH / AP)

DPRK's leader Kim Jong-un, center left, meets with ROK's President Moon Jae-in, center, as US President Donald Trump, center right, look on south of the Military Demarcation Line that divides DPRK and ROK, on June 30, 2019. (BRENDAN SMIALOWSKI / AFP)

DPRK's leader Kim Jong-un, left, and US President Donald Trump attend a meeting on the south side of the Military Demarcation Line that divides DPRK and ROK, on June 30, 2019. (BRENDAN SMIALOWSKI / AFP)

US President Donald Trump views DPRK from the Korean Demilitarized Zone from Observation Post Ouellette at Camp Bonifas in ROK, June 30, 2019 with ROK's President Moon Jae-in. (SUSAN WALSH / AP)

US President Donald Trump meets with DPRK's leader Kim Jong-un at the border village of Panmunjom in the Demilitarized Zone, June 30, 2019. (SUSAN WALSH / AP)

In this photo taken on June 30, 2019, US President Donald Trump meets with DPRK's leader Kim Jong-un at the border village of Panmunjom in the Demilitarized Zone. (SUSAN WALSH / AP)