BEIJING, May 6 (CGTN) -- China resolutely opposes U.S. navy's illegal entry to the South China Sea, condemning it as a way to undermine China's sovereignty and jeopardize peace, security and order in relevant waters, said Geng Shuang, a spokesperson for the Chinese Foreign Ministry, during a regular press conference on Monday.

Earlier Monday, two U.S. guided-missile destroyers Preble and Chung Hoon sailed near islands in the South China Sea without permission. Chinese warships and military aircraft responded immediately, identifying the U.S. warships, giving warnings and expelling them, he added.

China urges the U.S. to immediately stop provocations that infringe upon China's sovereignty and threaten China's security, said Geng, stressing that China will take necessary actions to maintain its sovereignty and territorial integrity.

Also on Monday, the Southern Theater Command of China's People's Liberation Army declared China's uncontested sovereignty over the islands in the South China Sea and the neighboring waters, warning that the PLA will closely monitor the situation and take all necessary actions to defend China's sovereignty and national security as well as the peace and stability in the South China Sea region, said the spokesperson Senior Colonel Li Huamin.