Sullivan and Cho met on the margins of the G-20 Foreign Ministerial Meeting, said a release.

"Deputy Secretary Sullivan and Vice Foreign Minister Cho affirmed that the U.S.-ROK Alliance is stronger than ever and pledged to maintain close coordination during this crucial time," the release stated.

Discussing North Korea, the two leaders agreed that global maximum pressure campaign is working against Kim and his government.

They also spoke about the upcoming historic meeting between Trump and Kim, which is scheduled to take place in Singapore on June 12.

"The two leaders noted that the upcoming meeting between President Trump and North Korean leader Kim Jong Un is an historic opportunity and evidence that the global maximum pressure campaign is working. The Deputy Secretary and the Vice Foreign Minister also discussed mutual G-20 priorities, bilateral economic cooperation, and trilateral initiatives with Japan," it said.

However, last week, reports about Kim threatening to boycott the meeting with trump has surfaced.

North Korea has said that they will contemplate cancellation if the US unilaterally insists the former gives up nuclear weapons.

The reclusive communist nation had also stalled the much anticipated North-South dialogues, which was originally scheduled for Wednesday.

The country has cited ongoing military exercises between the South and the United States as the reason behind cancelling the meet.

"The North's Korean Central News Agency said the Max Thunder drills between the South Korean and U.S. air forces are a rehearsal for invasion of the North and a provocation amid warming inter-Korean ties," reported South Korea's Yonhap News agency.

However, bilateral ties between the two Korean neighbours have seemingly improved in the recent past.

Kim also created history as he became the first leader to cross North Korean borders to hold a meeting with South Korea's President Moon Jae-in on Apr 27.

The two leaders holding an impromptu conversation while sitting on a park bench in the Panmunjom peace village also garnered much attention from the media and common public.

Image: twitter.com/statedeptspox