China is conducting "human testing" to create "biologically enhanced soldiers," the head of US intelligence has claimed as he warned that Beijing poses the biggest threat to America's national security. In an op-ed for the Wall Street Journal, John Ratcliffe, the director of national intelligence, warned that the US must be prepared for an "open-ended" confrontation with China which he likened to the Cold War. Mr Ratcliffe, who oversees America's intelligence agencies, said he believed China's intention was to "dominate" the planet in every sense: economically, militarily and technologically. He claimed that US intelligence showed China has "conducted human testing on members of the People’s Liberation Army in hope of developing soldiers with biologically enhanced capabilities". "There are no ethical boundaries to Beijing’s pursuit of power," he said. Mr Ratcliffe said his unique vantage point on the current security threats facing the US had led him to conclude that "the People’s Republic of China poses the greatest threat to America today, and the greatest threat to democracy and freedom world-wide since World War II". He went on to outline in granular detail China's strategy of economic espionage, which he framed as: “rob, replicate and replace.” “China robs US companies of their intellectual property, replicates the technology, and then replaces the US firms in the global marketplace,” he said.