Japan, the United States, Australia and the Philippines said Saturday they will conduct their first full-scale joint naval exercises in the South China Sea, in an apparent show of unity against China's maritime assertiveness, Paralel.Az reports citing Kyoto.

The Maritime Cooperative Activity will be held in the Philippines' exclusive economic zone on Sunday to demonstrate the "collective commitment to strengthen regional and international cooperation in support of a free and open Indo-Pacific," the four countries' defense ministers said in a joint statement.

Since holding the first meeting of their defense chiefs in June last year, the United States and its three allies have been beefing up their bilateral or multilateral ties.

China has become increasingly assertive in the resource-rich South China Sea. In the most recent incident, China's coast guard used water cannons against a Philippine ship near a disputed shoal late last month.

"We stand with all nations in safeguarding the international order based on the rule of law," which is the "foundation" of regional peace and stability, the four ministers said in the statement.

The joint drills will take place off the Philippines' Palawan Island, Philippine government sources said. The drills are aimed at strengthening the "interoperability" of their forces' "doctrines, tactics, techniques and procedures," the ministers said.

The exercises are expected to include anti-submarine warfare drills and maritime patrols, a Japanese Defense Ministry official told reporters, adding "no specific nations" are targeted.

In the water cannon attack by the Chinese Coast Guard near the Manila-controlled, Beijing-claimed Second Thomas Shoal, a Philippine vessel on a supply mission to a grounded navy ship was heavily damaged and Filipino servicemen were wounded.

In the statement, the ministers reaffirmed their position that a 2016 ruling by the Permanent Court of Arbitration that invalidated China's claim of sovereignty over almost the entire South China Sea was "a final and legally binding decision on the parties to the dispute."

In August, the four nations also held joint training for offshore replenishment off the northwestern Philippines, but the participants only exchanged salutes and assembled for a photo session.