The South Korean president, Moon Jae-in, will meet Donald Trump at the White House on Tuesday amid concern in Washington about next month's proposed summit with North Korea, following Pyongyang's apparent threat to withdraw from the historic meeting.
Mr Trump, who spoke to Mr Moon by phone on Saturday, will meet the South Korean leader in a bid to move preparations forward for the June 12th summit with Kim Jong-un in Singapore.
The White House was unnerved by the sudden change of tone from Pyongyang last week, according to several media reports, but preparations are still under way for what would be the first meeting between a North Korean leader and a sitting US president.
In a separate development Mr Trump defended his strategy on China after three days of relatively inconclusive trade talks. The Chinese delegation, led by Vice-Premier Liu He, travelled to Washington after tense talks in Beijing last month. Mr Trump has been highly critical of the United States' $370 billion trade deficit with China, and vowed to rectify it.
In an apparent victory for Beijing the US treasury secretary, Steve Mnuchin, confirmed that the United States would not impose threatened tariffs on up to $150 billion of Chinese imports, a move that had been threatened during the last round of talks. "We are putting the trade war on hold," he told Fox News.
The avoidance of an immediate trade war lifted stocks and the dollar on Monday, but the details of a trade plan with China remain elusive.
Mr Trump addressed the issue in a series of tweets on Monday. Complaining that Democrats and the previous administration did not “do something about Trade with China”, he said that “fair trade, plus, with China will happen!”
He also said China had agreed to buy "massive amounts of ADDITIONAL Farm/Agricultural Products", although there was no confirmation of any specific deal. Mr Trump's commerce secretary, Wilbur Ross, said the US had not conceded anything during the negotiations. "This is not a definitive agreement. This is what we hope will be a path forward. If it doesn't work the tariffs will go into effect, so nothing's been lost at all," he said.
As the president travelled to CIA headquarters to witness the official swearing-in of the agency's new head, Gina Haspel, on Monday, he also took aim in a series of tweets at the special-counsel investigation into Russian interference in the 2016 presidential election.
In a further development his deputy attorney general, Rod Rosenstein, and the director of the FBI, Christopher Wray, were due to meet Mr Trump at the White House on Monday over Mr Trump's request that the US department of justice investigate reports that an FBI informant infiltrated the Trump campaign. Mr Trump announced on Sunday that he would tell the department to look into whether it or the FBI "infiltrated or surveilled" his election campaign for political purposes.
In a statement Mr Rosenstein indicated that an investigation would be opened. “If anyone did infiltrate or surveil participants in a presidential campaign for inappropriate purposes, we need to know about it and take appropriate action,” he said.
Any move to appoint an inspector general may be insufficient for Trump supporters, however, given that he or she would not have full powers of subpoena.