China has intensified its war of words with America, almost a week after Pentagon officials allowed a CNN television crew aboard a surveillance flight over the South China Sea. Yesterday Hua Chunying, a spokeswoman for China’s foreign ministry, said her government had complained formally to the Americans, who should stop their “provocative behaviour”. The broadcast of a typically classified operation followed months of rapid island-building by China in the sea, control of which is disputed among the nations surrounding it. On Friday America’s vice-president, Joe Biden, said China’s land-reclamation had heightened tensions. Chinese officials and state media are meanwhile warning America against letting its naval vessels and aeroplanes get too frisky. An op-ed in Global Times, a state-owned nationalist newspaper, claimed that war was “inevitable” if America, which it called a “paper tiger”, did not soften its stance. That is surely bluster, but the air over the South China Sea is getting hotter.