A Type 054A frigate featured in video footage released by People's Liberation Army (PLA) Southern Theater Command (STC) Photo: screenshot from video footage released on STC's official WeChat account

China Coast Guard (CCG) vessels featured in a video footage released by CCG Photo: screenshot from video footage released on CCG's official WeChat account

Naval and air units of the Chinese People's Liberation Army (PLA) Southern Theater Command (STC) conducted readiness patrols in the territorial sea and airspace of China's Huangyan Dao and its surrounding areas on Friday, according to an official release from the STC. 

On the same day, the China Coast Guard (CCG) conducted law-enforcement patrols in the territorial sea of China's Huangyan Dao and its surrounding areas, the CCG announced.

Both the STC and CCG said that this is a necessary countermeasure in response to the Philippines' rights-violation and provocative acts.

The latest patrols came amid heightened tensions due to the Philippines' provocations, including making groundless accusations against China and the Chinese military and colluding with other countries in stoking confrontation at the ASEAN defense ministers' meetings held in Cebu, the Philippines. 

The patrols conducted by the STC and the CCG on the same day reflect China's continuously improving coordination capabilities in safeguarding territorial sovereignty and maintaining peace and stability in the South China Sea, and are highly targeted, Ding Duo, director of the Research Center for International and Regional Issues at the National Institute for South China Sea Studies, told the Global Times.

A video released by the STC showed that KJ-500 early warning aircraft, WZ-7 high-altitude reconnaissance drone, J-16 fighter jet, JL-10 advanced trainer jet, H-6K bomber armed with YJ-12 supersonic anti-ship missiles, and Type 054A frigate participated in the operation.

These weapons and equipment cover a wide range of missions, reflect the PLA's systematic deployment, diverse equipment types and comprehensive mission coverage, Ding noted. 

The video released by the STC showed Chinese naval aviation forces tracking and monitoring a Philippine C-208 military aircraft. A Chinese Air Force aircraft issued a verbal warning: "Philippine military aircraft C-208, you have intruded into China's airspace over Huangyan Dao. Leave immediately, or we will take measures against you. You will bear full responsibility for all ensuing consequences."

The STC and CCG's operations and a wider range of military equipment send a clearer signal to the Philippine military and law enforcement authorities, as well as forces outside of the region, Ding said. By demonstrating its capabilities and determination to maintain regional peace and stability, China is also sending a warning to forces seeking to stir up tensions in the South China Sea, he added.

"The operations were particularly targeted at the Philippines' attempts to draw external forces into the South China Sea and exploit the ASEAN defense ministers' meetings to advance its own agenda," Ding said.