WASHINGTON (Reuters) - The deputy White House national security adviser on Friday denounced China’s treatment of Uighur Muslims, saying there was no justification for the country maintaining “concentration camps” within its borders. Matt Pottinger, who has been a leading figure in the development of President Donald Trump’s China policy, made the remark in Mandarin in an online address to the U.K.-based Policy Exchange think tank. “There is no credible justification I can find in Chinese philosophy, religion, or moral law for the concentration camps inside your borders,” Pottinger said in his speech, which he said was directed to the Chinese people. It represented a further ratcheting up of American rhetoric against China in the run-up to the Nov. 3 U.S. presidential election, in which Trump, a Republican, has made a tough approach to China a key foreign policy theme. Last week, Pottinger’s boss, U.S. national security adviser Robert O’Brien, said China was perpetrating “something close to” genocide with its treatment of Muslims in its Xinjiang region. Pottinger called on people in China “to research the truth about your government’s policy towards the Uighur people and other religious minorities.” He said they should ask themselves why The Economist newspaper had called China’s actions in Xinjiang “a crime against humanity.” The United States has denounced China’s treatment of Uighur and other minority Muslims in Xinjiang and imposed sanctions on officials it blames for abuses. It has not, though, so far termed Beijing’s actions genocide or crimes against humanity, designations that would have significant legal implications and require stronger action against China. The United Nations estimates that more than a million Muslims have been detained in Xinjiang, and activists say crimes against humanity and genocide are taking place there. China has denied any abuses and says its camps in the region provide vocational training and help fight extremism. Pottinger said there was a growing consensus internationally about the need to take a more assertive stance with Beijing. He said that in a second term, Trump would continue working to diversify supply chains to avoid excessive reliance on one country - an apparent reference to China’s dominance of critical supplies laid bare at the start of the COVID-19 pandemic. Pottinger spoke after China’s President Xi Jinping delivered a speech on the 70th anniversary of Chinese troops entering the Korean War to fight against U.S. troops, in which he warned that China will never allow its sovereignty, security and development interests to be undermined. Xi did not directly refer to the present-day United States, with which relations have sunk to their lowest in decades over disputes ranging from trade and technology to human rights and the coronavirus. Reporting by David Brunnstrom and Andrea Shalal; editing by Jonathan Oatis Our Standards: The Thomson Reuters Trust Principles.