The Chinese People's Liberation Army (PLA) monitored, tracked and maintained a high level of alert as the U.S. Navy's guided-missile destroyer USS Milius trespassed into China's territorial waters near Meiji Reef in the South China Sea on Monday, said Tian Junli, a spokesperson for the PLA Southern Theater Command.

China has indisputable sovereignty over the islands and their surrounding waters in the South China Sea, Tian said in a statement on Monday.

The PLA Southern Theater Command will stay on high alert and safeguard national sovereignty and security as well as peace and stability in the South China Sea, he added.