The Chinese People's Liberation Army Southern Theater Command conducted joint air and maritime exercises on Sunday in the waters and airspace around Huangyan Island in the South China Sea.

The theater command said the exercises were necessary in response to actions by certain countries that undermine regional peace and stability.

The drills focused on combat-oriented tasks, including reconnaissance and early warning, rapid maneuvering, and joint search and rescue. They tested and enhanced troops' capabilities in air-maritime coordination, rapid support and integrated operations, according to a statement from the theater command.

The exercises were aimed at testing and enhancing troops' ability to safeguard national territorial sovereignty and maritime rights and interests under actual combat conditions, it said.

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In the meantime, the China Coast Guard conducted a rights-protection and law enforcement exercise in the waters around Huangyan Island on the same day, focusing on operations including boarding and inspection, intercepting vessels attempting to force their way through and forced towing.

Jiang Lue, a spokesman for the CCG, said it will step up law enforcement and rights-protection efforts in the waters around Huangyan Island to resolutely safeguard national territorial sovereignty and maritime rights and interests.

Experts said the exercises provided realistic, combat-oriented training for both the PLA and CCG, demonstrating their high level of combat readiness.

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Zhang Chi, a professor at PLA National Defense University, said the joint exercises served as a stern warning to the Philippines over its infringement and provocative actions, and were a necessary response to its continued efforts to undermine peace and stability in the South China Sea.

The joint exercises came after the Philippines violated relevant commitments and agreements by proceeding — despite China's warnings — with a resupply mission on Thursday to deliver supplies to a Philippine vessel that remains illegally grounded at Ren'ai Reef.

Zhang said the joint exercises conducted by China were "legitimate and necessary", adding that the standardized measures were necessary to safeguard China's territorial sovereignty and maritime rights and interests, as well as to maintain peace and stability in the South China Sea.

Contact the writers at lishangyi@chinadaily.com.cn