Photo/IllutrationA large street television in Tokyo's Chiyoda Ward reports North Korea's ballistic missile test over the Japanese archipelago in September 2017. (Asahi Shimbun file photo)

North Korea remains a security threat to Japan with its vast missile arsenal despite its promise to denuclearize, according to the Defense Ministry's fiscal 2018 white paper.

Defense Minister Itsunori Onodera reported on the white paper at a Cabinet meeting on Aug. 28.

It called the militaristic moves of North Korea “an unprecedentedly grave and imminent threat.”

In the paper, the ministry praised the historic summit between North Korean leader Kim Jong Un and U.S. President Donald Trump in June. It said it is “significant” that Kim promised “complete denuclearization of the Korean Peninsula.”

However, it also emphasized that Japan’s “fundamental recognition of its menace is unchanged,” as North Korea still retains and can deploy a few hundred mid-range Nodong ballistic missiles that can be ready to launch at a moment's notice.

The paper added that “it is necessary to ascertain” Pyongyang’s tangible steps toward disposal of its nuclear weapons and missiles.

It also revealed how Japan continues to be alarmed by China’s offshore activities.

It includes a photo of China’s de facto military base in Djibouti in northeast Africa that went into service from last August. It emphasized that China is showing “conspicuous moves to set up bases of operation at ports and other location abroad.”

The paper noted that the May agreement between Japanese and Chinese defense ministries to establish the Maritime and Aerial Communication Mechanism to avoid accidental sea and air clashes was "hugely significant."

However, it added that Japan will remain vigilant as the administration of the China Coast Guard, which has been patrolling off the disputed Senkaku Islands in the East China Sea, was transferred from civilian to Central Military Commission control in July.