Foreign Ministry spokesperson Lu Kang [Photo: fmprc.gov.cn]

BEIJING, May 27 (Xinhua) -- China on Sunday voiced strong dissatisfaction and firm opposition to two U.S. warships trespassing into China's territorial waters off the Xisha Islands.

Foreign Ministry spokesperson Lu Kang said in a statement released on Sunday night that the U.S. warships trespassed into China's territorial waters off the Xisha Islands on Sunday without permission of the Chinese government, and the Chinese navy identified the U.S. warships, warned and expelled them.

The Xisha Islands are China's inherent territory, Lu said, noting that in accordance with the Law of the People's Republic of China on the Territorial Sea and the Contiguous Zone, the Chinese government promulgated the baseline of the territorial sea off the Xisha Islands in 1996.

The relevant Chinese law has explicit provisions on foreign military vessels' entry into the territorial sea of China, Lu said.

The U.S. side once again sent warships to trespass into China's territorial waters off the Xisha Islands, an act which violated the Chinese and relevant international laws, seriously infringed upon China's sovereignty, disrupted peace, security and good order of the relevant waters.

"The Chinese side strongly urges the U.S. side to immediately stop such kind of provocative operations that violate China's sovereignty and threaten China's security," Lu said, noting that the Chinese side will continue to take all necessary measures to defend national sovereignty and security.