Japan is facing its most severe security environment since World War II as three potential adversaries in East Asia – China, Russia and North Korea – ramp up military activities in the region, the country’s defense minister said Tuesday.

“The existing order of world peace is being seriously challenged, and Japan finds itself in the most severe and complex security environment of the post-war era,” Defense Minister Gen Nakatani said in an introduction to the ministry’s annual defense white paper.

China’s military activities present “an unprecedented and the greatest strategic challenge” to Japan, the report said.

Beijing is “rapidly enhancing its military capability in a qualitative and quantitative manner” while “intensifying” activities around the region, Nakatani said, specifically mentioning the Senkaku Islands, a chain in the East China Sea that Tokyo controls but which is also claimed by Beijing, which calls them the Diaoyus.

The 34-page document gives a dire outlook on the future of the region, especially on the rivalry between China and the United States, Tokyo’s most important ally.