China accused Japanese Prime Minister Shinzo Abe of “maliciously slandering” its recently self-proclaimed air defense zone in a tongue lashing amid a bitter war of words.

The hawkish Japanese premier denounced Beijing’s annexation of airspace over a group of disputed islands in the East China Sea during a summit with the Association of Southeast Asian Nations in Tokyo.

Abe said China’s air defense identification zone “unjustly violates the freedom of aviation over high seas” as Tokyo called for cooperation to ensure the safety of seas and freedom of navigation in a joint statement with the 10-member regional bloc. The statement, however, did not openly criticize China.

“We express strong dissatisfaction with Japan’s leader using an international occasion to maliciously slander China,” Chinese foreign ministry spokesman Hong Lei said.

“The Diaoyus are an inherent territory of China. Japan’s seizure and occupation of the islands are illegal and invalid,” Hong said, arguing that the air zone was in line with international laws and practices, and did not affect aviation freedom.

“The Chinese side took necessary measure to safeguard its sovereignty and territorial integrity. This is totally legitimate and irreproachable.”

Beijing condemned Japan’s “tricks” and says its attempts to “mislead world opinion is doomed to failure.”

Japan has been shoring up relations with Southeast Asia in a bid to contain China’s reach in the region. China is embroiled in territorial disputes with several Asian nations.

Maesie Bertumen