U.S. President Donald Trump (R) and North Korea's leader Kim Jong Un (L) walk toward one another at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump reaches to shake hands with North Korea leader Kim Jong Un at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore. AP

U.S. President Donald Trump (R) shakes hands with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump (R) gestures as he meets with North Korea's leader Kim Jong Un (L) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump (R) holds out his hand for a handshake with North Korea's leader Kim Jong Un (2nd L) as they meet at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump (R) shakes hands with North Korea's leader Kim Jong Un as they meet at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

North Korea's leader Kim Jong Un (L) walks with U.S. President Donald Trump (R) at the start of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump shakes hands with North Korea leader Kim Jong Un during their first meetings at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore. AP

U.S. President Donald Trump (R) waves as he and North Korea's leader Kim Jong Un look on from a veranda during their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

President Donald Trump meets with North Korean leader Kim Jong Un on Sentosa Island, Tuesday, June 12, 2018, in Singapore. AP

North Korea's leader Kim Jong Un looks on while seated with members of his delegation during the US-North Korea summit with US President Donald Trump (not pictured) at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump and North Korea leader Kim Jong Un walk from lunch at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore. AP

U.S. President Donald Trump and North Korea leader Kim Jong Un walk from their lunch at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore. AP

North Korea's leader Kim Jong Un (R) walks with US President Donald Trump (L) during a break in talks at their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

U.S. President Donald Trump gestures toward North Korea leader Kim Jong Un seat before a document signing at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore. AP

North Korea's leader Kim Jong Un (L) shakes hands with U.S. President Donald Trump (R) after taking part in a signing ceremony at the end of their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

US President Donald Trump holds up a document signed by him and North Korea's leader Kim Jong Un following a signing ceremony during their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

North Korea's leader Kim Jong Un (L) and U.S. President Donald Trump leave following a signing ceremony during their historic US-North Korea summit, at the Capella Hotel on Sentosa island in Singapore on June 12, 2018. AFP

President Donald Turmp waves as North Korea leader Kim Jong Un leaves after their meetings at the Capella resort on Sentosa Island Tuesday, June 12, 2018 in Singapore. AP