The United States, Japan, Australia and the Philippines will hold their first joint naval exercises, including anti-submarine warfare training, in a show of force Sunday in the South China Sea where Beijing’s aggressive actions to assert its territorial claims have caused alarm.

The four treaty allies and security partners are holding the exercises to safeguard “the rule of law that is the foundation for a peaceful and stable Indo-Pacific region” and uphold freedom of navigation and overflight, they said in a joint statement issued by their defense chiefs Saturday.

China was not mentioned by name in the statement, but the four countries reaffirmed their stance that a 2016 international arbitration ruling, which invalidated China’s expansive claims on historical grounds, was final and legally binding.

China has refused to participate in the arbitration, rejected the ruling and continues to defy it. The Philippines brought its disputes with China to international arbitration in 2013 after a tense sea standoff.