The leaders of South Korea and the United States have agreed that it's important to maintain existing sanctions on North Korea until complete denuclearization is achieved.

President Moon Jae-in and U.S. President Donald Trump also agreed that a visit to Seoul by North Korean leader Kim Jong-un could create momentum for peace-building efforts on the Korean Peninsula.

Trump also hoped for a swift second summit with the North Korean leader to continue progress in the denuclearization process.

Moon's chief press secretary Yoon Young-chan said the two leaders held summit talks for half-an-hour on Friday on the sidelines of the Group of 20 Leaders' Summit in Buenos Aires in Argentina.

This marks Moon and Trump's sixth bilateral summit. They last met 67 days ago in September during the UN General Assembly in New York.

Friday's 30-minute meeting was the shortest of their summits so far.

It was a closed-door session with only the presidents and interpreters in attendance without their aides.

Moon and Trump agreed that the denuclearization and peace-building process on the Korean Peninsula was moving in the right direction and vowed to closely coordinate based on the firm Seoul-Washington alliance to achieve their joint goals at an early date.

Regarding whether Moon's agreement to maintain sanctions on Pyongyang was a change in his stance as he had called for easing sanctions, a senior presidential official told reporters that Moon has continuously said that it's necessary to boost mutual trust and this belief remains unchanged.

During the meeting, President Trump affirmed his commitment to holding a second summit with North Korea early next year and asked that South Korea and the U.S. closely cooperate so the next summit will be another historic milestone in the process of denuclearization.