BEIJING, Aug 5 (Reuters) – China's coast guard said it was monitoring Philippine patrol and fishing vessels gathered around the disputed Sabina Shoal, citing China's "undisputed sovereignty" over the Spratly Islands in the South China Sea.

The Chinese coast guard had been monitoring the vessels since Saturday, spokesman Gan Yu said in a statement Sunday evening.

Gan said patrol boats from the Philippine Bureau of Fisheries and Aquatic Resources and several fishing boats gathered in the waters near a Philippine vessel that China said was "illegally stranded" near the shoal.

The stranded ship "violates" China's territorial sovereignty and maritime rights and interests, and "undermines" peace and stability in the South China Sea, the Chinese coast guard reiterated.