OSAKA, Japan — President Trump said on Saturday that he would visit the Demilitarized Zone between North and South Korea on Sunday, and he publicly invited Kim Jong-un, the North’s iron-fisted leader, to meet him there for what would be their third get-together.

In a post on Twitter as he started the second of two days of meetings in Osaka, Japan, Mr. Trump said that during his next stop, in South Korea, he would be happy to greet Mr. Kim across the line that has divided Korea for nearly 75 years.

“I will be leaving Japan for South Korea (with President Moon),” the tweet said. “While there, if Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!”

[Analysis: Trump’s offer to say “hello” at DMZ presents risks and rewards for both.]

North Korea indicated on Saturday that it would welcome such a meeting.