The US Navy sent a destroyer near the Spratly Islands in the disputed South China Sea on Tuesday to “challenge restrictions on innocent passage imposed by China, Vietnam, and Taiwan”. The operation came after the United States military warned in a document last week that it would be “more assertive” against Beijing. The document set out objectives for the US Navy, Marines and Coast Guard for 2021. In a statement on Tuesday afternoon, Tian Junli, spokesman for the Chinese People’s Liberation Army’s Southern Theatre Command, said the destroyer USS John S. McCain sailed near the Spratly Islands, which China calls the Nansha Islands. “China is resolutely opposed to this kind of behaviour from the US that harms China’s sovereignty and security, which also seriously disrupts the peace and stability in the South China Sea,” Tian said, adding that the destroyer was driven away after it was warned by the PLA. A statement from the US Pacific Fleet Commander confirmed the exercise took place on Tuesday. “On December 22, USS John S. McCain (DDG 56) asserted navigational rights and freedoms in the Spratly Islands, consistent with international law,” the statement said. China claims almost all the islands in the South China Sea but those assertions are disputed by other players in the region, including Taiwan, Vietnam, Malaysia, the Philippines and Brunei. South China Sea: the dispute that could start a military conflict The US has been sending ships to the region more frequently recently to carry out what it calls “freedom of navigation” operations. According to Beijing think tank the South China Sea Strategic Situation Probing Initiative, the latest exercise by the USS John S. McCain was the ninth time this year that a US Navy vessel had sailed within 12 nautical miles of land claimed or occupied by China in the South China Sea – the most in the past five years. The US Pacific Fleet Commander statement said: “Unlawful and sweeping maritime claims in the South China Sea pose a serious threat to the freedom of the seas, including the freedoms of navigation and overflight, free trade and unimpeded commerce, and freedom of economic opportunity for South China Sea littoral nations.” But, in a rare move, the US criticised Taipei and Hanoi, in addition to Beijing, for requiring “either permission or advance notification before a foreign military vessel engages in ‘innocent passage’ through the territorial sea”, which the US statement said was against international law as reflected in the United Nations Convention on the Law of the Sea. “By engaging in innocent passage without giving prior notification to or asking permission from any of the claimants, the United States challenged the unlawful restrictions imposed by China, Taiwan, and Vietnam. The United States demonstrated that innocent passage may not be subject to such restrictions,” it said. A day before the exercise, the US Pacific Fleet reported on its Twitter account that the USS John S. McCain had joined the French Navy in the Philippine Sea to conduct drills.