China's foreign ministry expressed anger on Monday over two U.S. warships entering the South China Sea.

The Chinese side immediately conducted verification and identification on the U.S. ships and warned them to leave, ministry spokesperson Hua Chunying said at a daily news briefing.

The relevant action by the U.S. side infringed upon China's sovereignty, and undermined peace, security and order of relevant waters, Hua said, adding that China will continue to take necessary measures to safeguard itself.

China firmly opposed the relevant action and urged the U.S. side to immediately stop its provocations, Hua stressed.

The two guided-missile destroyers, USS Spruance and USS Preble, entered China's territorial seas around the Nansha Islands without permission from the Chinese government, said senior colonel Li Huamin, spokesman of the People's Liberation Army Southern Theater Command, on Monday.

Li echoed the foreign ministry's stance that the command will continue to watch closely Chinese waters to safeguard national sovereignty and security.