This photo carried by North Korea's state news agency on November 15, 2017, shows its leader Kim Jong-un (C) inspecting a tractor factory.
'Oh well, I try so hard to be his friend - and maybe someday that will happen!'
Tweeted Trump about the North Korean dictator: 'Why would Kim Jong-un insult me by calling me "old", when I would NEVER call him "short and fat?"
"[Trump is a] ugly criminal sentenced to death by the Korean people", Kim Jong-un's media said, according to Business Insider. "He will be forced to pay dearly for his blasphemy any moment". President Trump took offense to that statement, and in keeping with his usual method of criticizing those who upset him, he took to tweeting about it.
But the fact that Kim Jong Un's regime claims to be emboldened to keep improving the strength and range of their weaponry after each round of Trump rhetoric, is a legitimate cause for concern.
But Trump also offered a diplomatic opening to North Korea to "make a deal".
It is also another sign of the change in rhetoric used to address North Korea since Trump took office: Though North Korea has always been known for hurling bellicose insults at world leaders, rarely have those world leaders responded in kind.
"North Korea is not the paradise your grandfather envisioned", he added.
The break in testing matches lulls at similar times in past years and North Korea is nearly certainly continuing its push for more capable nuclear weapons, South Korean officials say.
Asked about the possibility of becoming friends with the North Korean leader during a news conference in Vietnam, Trump did not rule it out. In July, Trump publicly pondered if Kim didn't "have anything better to do with his life" than attempt missile launches in a tweet.
North Korea appears to have taken offense to Trump's detailed description of North Korea's bleak human rights situation during his speech before South Korea's National Assembly and his call for reunification.
On Sunday, Mr Trump said his Chinese counterpart stated "he is upping the sanctions against" North Korea, but China has not yet announced any new measures. Trump said the United States wanted "stability, not chaos" and "peace, not war". "If it did happen, it would be a good thing for North Korea, and a good thing for lots of other places and good for the world".