It might be fake news.

The first coverage of this news was reported by the Japanese media “Joint News”.

Other media in Japan ignored the news.

Other articles have different content. “Japan believes that maintaining the G7 framework itself is very important.” I haven't mentioned Korea in particular.

Here is the article. ↓

https://www.google.co.jp/amp/s/www.jiji.com/v/s/www.jiji.com/amp/article%3fk=2020062900408&g=use&amp_js_v=0.1&usqp=mq331AQFKAGwASA%253D#ampf =

At a press conference yesterday, Secretary-General Suga said it was important for Japan to maintain the G7 framework to expand the official members of the G7 Summit in the developed seven countries. Emphasized the opposite position. US President Trump has proposed that South Korea, Russia, India and others join the G7 Summit. (2020/06/29-12:27)