President Donald Trump extended an offer Saturday to North Korean dictator Kim Jong-un. In a unique round of Twitter diplomacy, the president invited Kim to meet him at the demilitarized zone between North and South Korea.

Trump revealed that he will travel to South Korea after attending the G20 summit in Japan.

“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(?)!” Trump wrote on Twitter. North Korea responded to Trump’s invitation through its state media.

“I consider this a very interesting suggestion, but we have not received any official proposal,” Choe Son-hui, North Korea’s first vice foreign minister, said in a statement.

Trump confirmed to reporters Saturday that the United States had heard from North Korea and had extended an official invitation.

“It will be very interesting,” he said when asked if the meeting would actually happen. “We’re going to see”:

Regardless, Trump plans to visit the DMZ and South Korean President Moon Jae-in on Sunday.