MANILA – Japan and the Philippines pledged to boost defense ties as both nations expressed concern over China’s establishment of an air defense identification zone in the East China Sea.

“Both of us have affirmed that China’s unilateral action to change the status quo by force or coercive action will bring back tension in this region,” Defense Minister Itsunori Onodera told reporters in Manila on Saturday after meeting with his Philippine counterpart, Voltaire Gazmin. They agreed to “expand and deepen” cooperation on “defense authorities,” he said.

Japan and the Philippines are also boosting ties with other nations as they seek to counter China’s increasing assertiveness in staking territorial claims. Japan, China and Taiwan are disputing sovereignty over the Senkaku Islands, which China claims as Diaoyu and Taiwan as Tiaoyutai. The Philippines and China meanwhile have conflicting claims over areas of the fish- and gas-rich South China Sea.

Specifics on expanded cooperation will be discussed by a working group, Onodera said. In June, Japan and the Philippines agreed to cooperate on the “defense of remote islands” and “protection of maritime interests” during Onodera’s first visit to the country.

Japan and the U.S. “have been firmly and calmly continuing patrol and surveillance in the area” under dispute and it is important for the international community to express concern, Onodera said.