Seoul — North Korea on Tuesday described President Donald Trump as a leader who frequently tweets "weird articles of his ego-driven thoughts" and "spouts rubbish" to give his assistants a hard time.The North's official Korean Central News Agency made the comments in response to tough talk in Washington and Seoul over threats posed by Pyongyang's nuclear and missile programmes.In the same commentary, KCNA also criticised South Korea's "puppy-like" Defense Minister Song Young-moo, who it said was "running wild" while relying on the "master of the White House". Song recently ordered the South's military to be prepared to "immediately and sternly punish" any kind of provocation by North Korea, which has caused hostility with two intercontinental ballistic missile tests last month and a threat to lob missiles toward the US territory of Guam.'Mad man'"Trump spouted rubbish that if a war breaks out, it would be on the Korean Peninsula, and if thousands of people die, they would be only Koreans and Americans may sleep a sound sleep," KCNA wrote, ridiculing Song for "pinning hope on that mad guy".The agency's comments came hours after North Korea's military issued its standard fiery threats over ongoing joint military exercises between the US and South Korean militaries, vowing "merciless retaliation" for exercises Pyongyang claims are an invasion rehearsal. The allies describe the annual war games as defensive in nature.North Korea has unleashed personal attacks on past Washington and Seoul leaders, calling former President Barack Obama a monkey and ex-South Korean President Park Geun-hye a prostitute. Trump was previously described in North Korean state media as "going senile" and a "war maniac bereft of reason."Trump talksTrump has used Twitter to launch his own insults at North Korea and its leader, Kim Jong Un. On August 11, Trump tweeted that military solutions were "fully in place, locked and loaded, should North Korea act unwisely" amid the standoff between Washington and Pyongyang over the Guam missile threat. But he complimented Kim five days later for making a "very wise and well reasoned decision" after Pyongyang walked away from the threat.After a July missile test by North Korea, Trump went on Twitter to ask whether Kim has "anything better to do with his life?" ''Hard to believe that South Korea ... and Japan will put up with this much longer. Perhaps China will put a heavy move on North Korea and end this nonsense once and for all!" Trump wrote.