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.

Japan has warned of escalating military threats from China in a new defense report. The report highlights China's growing military activity near Japan’s southwestern coasts and the Pacific as a major strategic challenge.

Japan says China’s military has posed serious challenges to its security, citing the first case of a Chinese military aircraft entering its airspace last August.