Calling Trump "mentally deranged" and his comments "the most ferocious declaration of a war in history", Kim said his United Nations speech on Tuesday confirmed Pyongyang's nuclear programme has been "the correct path".
His comments were believed to be the first direct message ever issued by a North Korean leader.
North Korea joined the Nuclear Nonproliferation Treaty in the mid-1980s but it "cheated" and was never held accountable, he said. She said there will be a very concerted and determined worldwide response to such action.
President Donald Trump added economic action to his fiery military threats against North Korea on Thursday, authorizing stiffer new sanctions in response to the Koreans' nuclear weapons advances.
South Korea's Unification Ministry spokesman Baik Tae-hyun told reporters Friday that North Korea must immediately stop such a provocation and return to talks on its nuclear disarmament.
"We have to assume they could do it, but it is exceedingly provocative", he said.
Despite strong opposition from China and Russian Federation against military actions on the Korean Peninsula, both Beijing and Moscow would hesitate to come to Pyongyang's rescue, as they did in the 1950s, in the event of a strike on North Korea by the United States, the Beijing-based expert argued.
"His remarks. have convinced me, rather than frightening or stopping me, that the path I chose is correct and that it is the one I have to follow to the last", Kim said in the statement carried by the North's official KCNA news agency, promising to make Trump "pay dearly for his speech".
It could also lead to all-out nuclear war. There is a recent report from the U.S. Geological Survey of a magnitude 3.5 natural disaster that occurred 22km ENE of Sungjibaegam, North Korea around 6:29 p.m. ChST.
Exported refined oil products must be used fully on civil purposes, not for North Korea's nuclear and ballistic missile programmes, or other activities banned by the UN Security Council, the ministry said.
"Through such a prolonged and arduous struggle, now we are finally only a few steps away from the final gate of completion of the state nuclear force", Ri told the annual gathering of world leaders for the United Nations General Assembly.
Ri, who was talking to reporters in NY ahead of a planned address later this week, however also said he did not know Kim's exact thoughts, according to the report.
North Korea conducted its sixth and most powerful nuclear bomb test on September 3, prompting another round of United Nations sanctions.
Such a test would be considered a major provocation by Washington and its allies.