China accused America of “serious military provocation” after a US Navy destroyer sailed within 12 nautical miles of an artificial island in the South China Sea – one day after the first move in what could develop into a full-blown trade war between the world’s two largest economies. Beijing also announced it was staging a naval drill in the disputed waters on Friday, but said it was not targeted at any specific country. The Chinese defence ministry said the USS Mustin had been “warned off” by two Chinese frigates. An anonymous US official told Reuters that the destroyer was carrying out a “freedom of navigation” operation, passing within 12 nautical miles of Mischief Reef in the Spratly Islands, where China has built an artificial island. It was America’s first such operation since January and came a day after US President Donald Trump announced it would levy US$60 billion worth of tariffs on Chinese imports – triggering immediate retaliation from Beijing. China to levy tariffs on US agricultural and steel products after US$60 billion Trump penalties “What the US is doing will damage the military-to-military relations and atmosphere,” said Ren Guoqiang, a spokesman for the Chinese defence ministry. “It could easily cause misjudgments and accidents at air or sea. This is a serious political and military provocation to China and the Chinese military is firmly objecting to this.” He said the action would push China to boost its defence capability in the region. The warning came as Beijing announced it was staging a combat exercise in the South China Sea on Friday. “According to the PLA Navy personnel department, this is routine training as part of its annual plan to improve combat capability, and it is not aimed at any specific country or target,” official news agency Xinhua reported. Hong Kong vows to hit back against any ‘discriminatory’ US trade actions Ni Lexiong, a Shanghai-based military expert, believed the US had deliberately timed the challenge to Beijing – sailing near its outpost – for the same day China hit back at America’s punitive tariffs. “This is a gesture, and it’s a combination of economic and military pressure,” he said. The PLA drill was planned at the beginning of the year and would take place within Chinese waters, state-run tabloid Global Times said. Observers were watching to see if China’s aircraft carrier, the Liaoning, would take part in the exercise, it said. China refused to recognise an international tribunal ruling in 2016 that invalidated its claim over most of the resource-rich South China Sea. Its territorial claims are disputed by a number of countries in the region, and Beijing has continued to build islands and infrastructure in the disputed waters. The Pentagon has meanwhile identified China and Russia as its two biggest military threats.