BEIJING, Feb. 4 -- "The air force of the Chinese PLA Southern Theater Command conducted a routine patrol in the airspace of China's Huangyan Dao on February 4," said a spokesperson for the Chinese PLA Southern Theater Command (STC) in a written statement on Tuesday.

The spokesperson pointed out that the Philippines has been colluding with countries outside the region to organize the so-called "joint patrols" to deliberately undermine peace and stability in the South China Sea.

The air force of the Chinese PLA STC will remain on high alert to resolutely defend China's territorial sovereignty and maritime rights and interests. Any military activities that disrupt the South China Sea are fully under control, stressed the spokesperson.