China's Foreign Ministry has expressed "grave concern" over Japan's deployment of long-range missiles capable of striking what Tokyo calls "enemy bases".

On Tuesday, claiming that Japan "faces the most severe and complex security environment in the postwar era", Japanese Defense Minister Shinjiro Koizumi announced the deployment of long-range missiles, capable of striking "enemy bases", in the country's Kumamoto and Shizuoka prefectures.

ALSO READ: Japanese protest over deployment of long-range missiles

Koizumi added that Japan must build up its ability to defend itself from outside the region.

On Wednesday, Chinese Foreign Ministry spokeswoman Mao Ning responded that, despite the use by Tokyo of terms such as "defense" and "counterattack", Japan's deployment of offensive weapons far exceeds the scope of "self-defense" and "exclusive defense".

READ MORE: Japan deploys long-range counterstrike missiles despite opposition

According to Mao, the move "seriously violates the provisions of documents which have the binding force of international law, such as the Cairo Declaration, the Potsdam Proclamation and the Instrument of Surrender of Japan, and this seriously violates Japan's Constitution and its existing domestic norms".

"This once again shows that Japan's far-right forces are pushing security policies toward offensiveness and expansionism," she said.