Unification minister Kim Yung-ho has stressed that the cooperation among South Korea, the U.S. and Japan is stronger than ever and therefore North Korea cannot reach Washington or Tokyo without going through Seoul first. 

Kim made the remark in an interview with Arirang TV on Friday with regard to the powerful sister of North Korean leader Kim Jong-un who hinted at the possibility of improving North Korea-Japan ties. 

The minister said the only way for Pyongyang to get out of diplomatic isolation is to decide to scrap its nuclear ambitions as demanded continuously by the international community. 

Kim said he believes the North would have been greatly shocked by the announcement that South Korea and Cuba established diplomatic relations.

Citing the issue of Japanese abductees in the North as an obstacle to improving Pyongyang-Tokyo ties, Kim said whether or not such an issue can be addressed will serve as a crucial indicator in enhancing bilateral relations.