The paper said North Korea's nuclear and missile programs have reached "a new level of threat" to Japan and the international community while last year's white paper said they posed "serious and imminent threats."

Japan's Defence Minister Itsunori Onodera attends a news conference at Defence Ministry in Tokyo, Japan August 8, 2017 (Issei Kato)

The Defense Ministry expressed strong concerns over maritime assertiveness in the East China Sea. The report said China's naval forces are constantly appearing near the Japanese-controlled Senkaku/Diaoyu Islands in the East China Sea and are tending to expand their activities in the southern part of the area where the islands are located.

On US security policies under President Donald Trump, the report said the US is strengthening its military presence toward North Korea to ensure their denuclearization. It also said US forces are stationed in Japan not just for Japanese benefit but also for the US, enabling a more rapid response to contingencies in the Asia-Pacific region.