BEIJING, Sept. 14 (Xinhua) -- The Chinese People's Liberation Army (PLA) Southern Theater Command conducted routine patrols in the South China Sea on Friday and Saturday, a spokesperson said on Sunday.

Tian Junli, the command's spokesperson, said the Philippines had colluded with countries outside the region for so-called "joint patrols," spread illegal claims about the South China Sea, and undermined peace and stability in the region.

"We solemnly warn the Philippine side to immediately stop provoking incidents and engaging in actions that heighten tensions in the South China Sea," Tian said, while adding that seeking external support would prove futile.

Tian emphasized that troops of the Southern Theater Command remain on high alert to resolutely safeguard China's territorial sovereignty and national security, and to uphold peace and stability in the South China Sea.

"Any attempt to stir up trouble or disrupt order in the South China Sea is doomed to fail," said the spokesperson. ■