Xi and Trump are next expected to meet again in Hamburg during the G20 Summit next month. Chinese efforts to help have "not worked out", Trump tweeted Tuesday.
And in January 2015, North Korea's state-run Korean Central News Agency (KCNA) said that if the U.S. would temporarily suspend its joint military exercises with South Korea, "North Korea would also be willing to respond by temporarily suspending the nuclear tests that the USA is concerned about".
The US administration is undoubtedly up in arms over the recent death of American Otto Warmbier following his incarceration in a North Korean prison, but this looks and feels like a public shaming and must count as one of the most controversial exchanges between a US President and his counterpart in China. Citing the fates of Iraq's Saddam Hussein and Libya's Moammar Gaddafi, the North Koreans repeatedly said that their nuclear program is the ultimate life preserver for the regime.
China, North Korea's main trading partner, has been accused of not fully enforcing existing United Nations sanctions on its neighbor, and has resisted some tougher measures.
Washington has considered further "secondary sanctions" against Chinese banks and other firms doing business with North Korea, which China opposes.
"What we do is to develop friendly and cooperative relations on the basis of five principles of peaceful coexistence", the spokesman, Geng Shuang, told a regular briefing on Thursday.
Trump has previously shown little willingness to work together on Chinese President Xi Jinping's signature project to build new trade and investment links between Asia, Europe and Africa.
The University of Virginia student was held in January last year while touring North Korea and was sentenced to 15 years hard labour after being convicted of stealing a propaganda poster from his hotel room. "At least I know China tried". The consideration came as Trump called the North's captivity of the now-deceased Warmbier a "total disgrace". Since his April meeting with Xi in Florida, Trump has toned down the anti-China rhetoric he campaigned on, and sent Matt Pottinger, the National Security Council's senior director for east Asia, as the United States representative at China's first Belt and Road Forum in May.
The security talks between USA and Chinese diplomats and defense chiefs are occurring amid outrage in Washington over the death of Otto Warmbier days after the American student was released from imprisonment in North Korea in a coma.
Beijing, which wants resumed USA negotiations with North Korea, was hoping for "positive outcomes" from Wednesday's dialogue, Chinese foreign ministry spokesman Geng Shuang said. But it was unclear if Pyongyang was preparing for a sixth nuclear test.