Japan’s Chief Cabinet Secretary Yoshihide Suga has criticized South Korea's National Assembly Speaker Moon Hee-sang over his rally of words with Tokyo demanding an apology from Emperor Akihito over the issue of wartime sexual slavery. 

During a media briefing on Monday, Suga responded to a question about Speaker Moon's refusal to apologize for his words while arguing Tokyo is the one to apologize. 

The Japanese minister said it is very regrettable for Moon to continue what he called inappropriate remarks, urging the speaker to withdraw his demand and made amends.

In an interview with Bloomberg early this month, Speaker Moon said Akihito should deliver the apology before he abdicates in April, adding he is the son of the main culprit of Japan's war crimes.

Although he drew strong criticism from Japanese leaders, including Prime Minister Shinzo Abe, Moon hit back, accusing his critics of being politically driven. 

He also denounced Tokyo for refusing to apologize over the sexual slavery issue, accusing it of playing the victim.