US President Donald Trump has said Chinese efforts to persuade North Korea to rein in its nuclear program have failed. <br/><br/>He said this a tweet. Trump has hardened his rhetoric against North Korea following the death of a US student after returning from captivity in North Korea in a coma.<br/><br/>The US President has held high hopes for greater cooperation from China to exert influence over North Korea, leaning heavily on Chinese President Xi Jinping for his assistance. <br/><br/>The two leaders had a high-profile summit in Florida in April and Trump has frequently praised Xi while resisting criticizing Chinese trade practices.<br/><br/>Meanwhile, China said on Wednesday it is making unremitting efforts on the North Korean nuclear issue. <br/><br/>The statement came after US President Donald Trump said Beijing had tried but failed to persuade Pyongyang to rein in its nuclear weapons programme. <br/><br/>Chinese Foreign Ministry spokesman Geng Shuang made the comment at a daily news briefing.