BEIJING, Aug. 10 -- China on Thursday voiced strong protest against a U.S. Navy warship passing close to the Meiji Reef of the Nansha Islands in the South China Sea.

The USS John S. McCain illegally entered the waters near the reef and conducted a so-called "freedom of navigation operation" on Thursday without permission of the Chinese government, Chinese Foreign Ministry spokesperson Geng Shuang said, adding the Chinese Navy identified the U.S. warship, warned and expelled it.

"Such a move severely undermines China's sovereignty and security, and severely endangers the safety of frontline personnel of both sides," he said.

"China has indisputable sovereignty of the Nansha Islands and its adjacent waters," Geng said.

With joint efforts of China and ASEAN members, the current situation in the South China Sea has stabilized and maintains a sound development momentum, he said, noting the recent China-ASEAN foreign ministers' meeting adopted the framework of the Code of Conduct (COC).

However, some parties from outside continue to meddle in the region under the guise of "free navigation," Geng said. "It is clear who is not willing to see stability in the South China Sea and who is the major factor pushing for militarization in the South China Sea."

"China has the firm determination to safeguard its territorial sovereignty and maritime interests," Geng said, reiterating that the U.S. provocation will force China to take further measures to strengthen homeland defense capacity.