Two Chinese fighter jets were monitored "orbiting" a Philippine aircraft participating in patrols with Australia in the South China Sea but did not cause any untoward incident, Manila said on Sunday.

The militaries of the Philippines and Australia carried out a second day of sea and air exercises in the Southeast Asian country's exclusive economic zone, days after Manila held patrols with the U.S. as Pacific nations warily eye an increasingly assertive China.

China claims almost the entire South China Sea, a conduit for more than $3 trillion of annual ship-borne commerce, including parts claimed by the Philippines, Vietnam, Indonesia, Malaysia and Brunei. The Permanent Court of Arbitration in 2016 said China's claims had no legal basis.