Japan has expressed regret over South Korea's removal of Tokyo from its list of trusted partners in the trading of strategic items. 

Japanese public broadcaster NHK quoted an official from the Ministry of Economy, Trade and Industry as saying on Wednesday that it's regrettable that Japan was removed from a list of countries entitled to preferential treatment in trade with South Korea.

The official reportedly added that the move was made without providing a "clear explanation." 

The ministry said that Japan is an adherent to all international export control regimes and implements a strict system to block materials from being used to make weapons of mass destruction and other weapons.

It added that Japan is analyzing the possible effects of the delisting on Japanese companies. 

Kyodo News and other Japanese media outlets framed Seoul's latest move as a retaliatory measure to Tokyo's removal of South Korea from its own list of trusted trade partners last month.