Given how ardently the US had sought the cooperation of Chinese President Xi Jinping, Trump upended much of that work in 140 characters, tweeting that Chinese efforts have “not worked out”. “While I greatly appreciate the efforts of President Xi and Chi to help with North Korea, it has not worked out. At least I know Chi tried,” Trump wrote. The tweet, which came hours before the US and Chi were set to meet in Washington to talk about North Korea, caught multiple Trump administration officials off guard, leaving them scrambling as they tried to figure out what exactly the President meant, CNN reported.