That meeting is expected to be followed by a planned Trump-Kim summit meeting by May. If that meeting takes place, Mr. Trump will be the first-ever sitting American president to meet a North Korean leader; Washington and Pyongyang are still technically at war because the 1950-53 Korean War was halted with a truce, rather than a peace treaty.

While presiding over a meeting Wednesday of government officials preparing for the inter-Korean summit, Mr. Moon attached great significance to the venue for his coming meeting with Mr. Kim.

“The North Korea-United States summit, which will follow the inter-Korean summit, will itself be a momentous event in world history,” Mr. Moon said. “Depending on where the meeting takes place, it will look even more dramatic, and depending on progress, there can be a three-way summit among South and North Korea and the United States.”