China is banning fishing off the coast of its troubling frenemy North Korea, and Japanese officials say there are increasing threats from its neighbors.

Beijing is ordering Chinese fishing trawlers to stay away from the waters off the eastern coast of North Korea, due to a dispute over fuel supplies.  In June, Pyongyang declared that Chinese trawlers had to buy fuel from North Korean suppliers, rather making their own arrangements as in the past.

Chinese official media also says North Korea’s east coast is subject to the “complex, changeable situation on the Korean peninsula”.  It’s another stinging rebuke from the only nation that calls North Korea an ally.

Meanwhile, Japan’s defense ministry also accuses the unpredictable nature of North Korea and China’s growing assertiveness in calling for building up the military.

“China has attempted to change the status quo by force based on its own assertion, which is incompatible with the existing order of international law,” the report said, two weeks before Japan’s upper house elections.

Hawkish Prime Minister Shinzo Abe wants to change the constitution to allow for more pro-active missions by Japan’s armed forces, currently restrained by the pacifist, post-World War II constitution.