Donald Trump has cancelled a planned trip by the US Secretary of State to North Korea.
Mike Pompeo, along with the new Special Representative for North Korea Stephen Biegun, had been due to travel to the secretive state next week.
President Trump today said he has asked Mr Pompeo to not travel to Pyongyang for now, suggesting "we are not making sufficient progress with respect to the denuclearisation of the Korean Peninsula".
In a series of tweets, he also claimed that China is 'not helping with the process of denuclearisation as they once were' due to the ongoing trade war between Washington and Beijing.
However, the US President also said he was looking forward to meeting North Korean leader Kim Jong-Un 'soon'.
...Secretary Pompeo looks forward to going to North Korea in the near future, most likely after our Trading relationship with China is resolved. In the meantime I would like to send my warmest regards and respect to Chairman Kim. I look forward to seeing him soon!
— Donald J. Trump (@realDonaldTrump) August 24, 2018
Mr Pompeo has already made a number of trips to Pyongyang, including several in the lead-up to the high-profile talks between Donald Trump and Kim Jong-Un earlier this year.
US officials have insisted that Kim agreed to "final, fully verified denuclearisation" at the Singapore summit in June.
Today's comments by President Trump marked a rare official acknowledgement of slow progress towards that goal.
Reports have suggested that the North Korean regime has not stopped its nuclear and missile programmes, in violation of international sanctions.
However, the summit has led to some cooling in the tense relations between the US and North Korea.
Last month, Pyongyang returned the remains of what are believed to be US servicemen killed during the Korean War - a development President Trump hailed as the North Korean leader 'keeping his word'.