Photo/IllutrationForeign Minister Toshimitsu Motegi, right, and his Chinese counterpart Wang Yi shake hands after giving a press statement following their meeting in Tokyo on Nov. 25. (Pool Photo via AP)

Foreign Minister Toshimitsu Motegi on Monday told his Chinese counterpart that he is highly concerned about the Hong Kong situation and it is important that a free and open Hong Kong keeps on prospering under the "one country, two systems" model, a Japanese government official said.

The official talked to a media briefing after a meeting in Tokyo between Motegi and China's state councilor and foreign minister, Wang Yi.

Prolonged pro-democracy protests in Hong Kong are posing the biggest popular challenge to Chinese President Xi Jinping since he came to power in 2012.