The planned summit between the United States and North Korea could become a three-way meeting with reports that South Korean President Moon Jae-in could join in the talks, Yonhap News reported.

Citing a ranking government official in South Korea's presidential office, the news agency said early Monday morning the decision would depend on how discussions proceed with U.S. and North Korean officials who are currently planning the meeting.

"The discussions are just getting started, so we are still waiting to see how they come out, but depending on their outcome, the president could join President Trump and Chairman Kim in Singapore," the unnamed official told Yonhap.

The idea of a three-way summit was first broached when Kim and Moon held their first-ever meeting late last month on the border village of Panmunjom. If the three-way summit is held, it is likely to include a discussion of a security guarantee for North Korea in exchange for denuclearization, Yonhap reported.

"Should the North Korea-U.S. summit succeed, I would like to see efforts to formally end the (Korean) war through a three-way summit of the South, the North and the U.S.," Moon said at a press briefing.

The summit is scheduled to take place in Singapore around June 12.