The New York Times says that the tweet is “an extraordinary admission of failure in his strategy” in dealing with Kim.

China’s efforts to rein in North Korea’s nuclear programme “have not worked” out, United States President Donald Trump has said but appreciated Beijing for its attempts.

“While I greatly appreciate the efforts of President Xi & China to help with North Korea, it has not worked out. At least I know China tried!,” Mr. Trump said in a tweet which came hours before the U.S. and China were set to meet in Washington to talk about North Korea.

In a report, The New York Times said that the tweet is “an extraordinary admission of failure in his strategy” for dealing with the rogue regime of Kim Jong-un.

US Secretary of State Rex Tillerson and the Defence Secretary James Mattis met in Washington for their diplomatic and security dialogue.

US has been very forceful: Spicer

White House press secretary Sean Spicer said the United States has been very forceful in its political and economic pressure that has been applied in North Korea.

“I think we’ll continue to apply that. Obviously, China has played and can continue to play a greater role in helping to resolve this situation, and we will continue to hopefully build on the relationship and the dialogue that we’ve had with China,” Mr. Spicer said.

“I think there have been some positive steps that they’ve taken, both at the UN and economically, to help strengthen the case against North Korea. But I’m not going to get ahead of where we may or may not go. And obviously, we hope that those discussions with China are productive and continue to move us forward,” he said.

Mr. Trump had made clear earlier that his preference was to work with China on North Korea, but that he was willing to go after them alone.

“I have great confidence that China will properly deal with North Korea. If they are unable to do so, the US, with its allies, will! U.S.A.,” he had tweeted in April.

Trump, Xi see thaw in ties

Chinese President Xi Jinping met with Mr. Trump at the President’s private Florida estate in April, a meeting that both leaders said warmed relations between the countries.