TOKYO -- Pyongyang responded to U.S. President Donald Trump's tweet offering to meet with North Korean leader Kim Jong Un less than an hour after the message was posted, Japanese Foreign Minister Taro Kono said here Monday.

Kono cited a telephone briefing on Sunday's summit by U.S. Secretary of State Mike Pompeo. The secretary said Washington was skeptical that Kim would show up until he actually arrived, according to Kono.

The invitation came early Saturday morning local time, shortly before Trump departed Japan for South Korea to meet with President Moon Jae-in.

"If Chairman Kim of North Korea sees this, I would meet him at the Border/DMZ just to shake his hand and say Hello(?)!" he tweeted.

Tokyo's chief diplomat also expressed interest in having Kim meet with Japanese Prime Minister Shinzo Abe.

"Japan must engage in direct dialogue to resolve the abduction issue," Kono said, referring to North Korea's kidnappings of Japanese nationals in the 1970s and 1980s. "We will prepare thoroughly so that we can start right away at any stage."

Trump and Pompeo conveyed Japan's stance to Pyongyang once again, and "North Korea is well aware of it," Kono said.