North Korean state media said this week that "no-one can predict when the lunatic old man of the White House, lost to sense, will start a nuclear war", referring to Trump's aggressive rhetoric toward Kim Jong Un.
Trump is overseas on a 12-day Asia-Pacific trip during which he has been meeting with regional leaders with a heavy emphasis on curbing North Korea's nuclear and missile programs. It's all documented. With President Donald Trump, some people do think that his Twitter and overall personality could make a nuclear exchange more likely.
North Korea's foreign ministry said of the comments, "Reckless remarks by an old lunatic like Trump will never scare us or stop our advance".
Following his trip to Hanoi, he flew to the Philippines after what he claimed was a "a great day of meetings and events", suggesting progress had been made in opposing North Korea and Jong-un.
The threat of conflict between Kim Jong-un's nuclear-armed North and the South, backed by Donald Trump, has been looming over the Korean Peninsula for months.
"Every step you take down this dark path increases the peril you face".
"Strange things happen in life".
At a news conference in Vietnam on Sunday after his tweets, Trump said it was possible he could be friends with Kim one day and that it would be "very, very nice" but he was not sure that it would happen. "If that did happen, it would be a good thing for, I can tell you, for North Korea".
Trump has traded insults and threats with Kim in the past amid escalating tension over Pyongyang's nuclear and missile programs as North Korea races toward its goal of developing a nuclear-tipped missile capable of reaching the United States -something Trump has vowed to prevent.
Trump hasn't always been a rhetorical foe of Kim.
"Together we have in our power to finally liberate this region and the world from this very serious nuclear menace, but it will require collective action, collective strength and collective devotion to winning the peace", Trump said.
Three days after Tillerson said he was "pleased to see that the regime in Pyongyang has certainly demonstrated some level of restraint that we've not seen in the past", North Korea fired three short-range ballistic missiles into the Sea of Japan. Earlier this year, he called the North Korean dictator a "smart cookie".