"The actions of the US vessels constitute a brusque violation of China's sovereignty, undermine peace, security and order in the relevant waters. The Chinese party expresses extreme dissatisfaction and a strong protest," Hua told a briefing.
She stressed that China had "indisputable sovereignty" over the islands and respected the freedom of navigation in the South China Sea but would not tolerate the use of this freedom as pretext for undermining the country's sovereignty and security.
"We strongly call on the US party to immediately stop these provocative actions… The Chinese party will take all necessary measures to resolutely defend its sovereignty and security as well as the stability in the South China Sea," the spokeswoman underlined.
China and several other countries of the region — namely Japan, Vietnam and the Philippines — have disagreements over maritime borders and areas of responsibility in the South China and East China Seas. China considers the Spratly Islands its territory, despite the Hague-based Permanent Court of Arbitration ruling that there was no legal basis for China's maritime claims. The arbitration proceeding was initiated by the Philippines in January 2013.