On Sunday morning following reports North Korea had conducted a "very important test" at its Sohae satellite launch station, Trump suggested in a tweet the North Korean leader should be careful about next steps.
"Kim Jong Un is too smart and has far too much to lose, everything actually, if he acts in a hostile way. He signed a strong Denuclearization Agreement with me in Singapore," Trump tweeted. "He does not want to void his special relationship with the President of the United States or interfere..."
North Korea replied to the tweet on Monday.
Kim Yong Chol, the top North Korean negotiator who met with Trump at the White House and was identified as chairman of the Asia-Pacific Peace Committee, suggested Trump lacked awareness of the issues.
"Trump knows so little about [North Korea]," Kim said. "We are a people who now have nothing to lose."
Kim Yong Chol added, "Trump seems to be very nervous. He is a careless and spiteful old man; a time when we'll have to call him a 'senile dotard' could come again."
North Korea has increased its war of words targeting the Trump administration since the breakdown of talks in Sweden in October.
Bono reportedly thanked Moon for making peace a reality, a reference to Moon's pro-engagement policy with the North that began in 2018.
Moon said music plays a critical in the peace process; Bono agreed "music is powerful" and that musicians of the North and South could play a role in the peace process.
Earlier over the weekend Moon exchanged a 30-minute phone call with Trump following North Korea's claimed test. The South Korean president did not hold his regular meetings of senior aides on Monday, according to KBS.