In a unanimously agreed statement, the 15-member UN Security Council said it was of vital importance that North Korea show "sincere commitment to denuclearization through concrete action and stressed the importance of working to reduce tensions".
US Secretary of State Rex Tillerson has urged North Korea to help foster an atmosphere conducive to talks by putting an end to its ballistic missiles and nuclear weapons tests.
Kim also dismissed allegations that the Democratic People's Republic of Korea - the country's official name - was behind the recent wave of global cyberattacks as "ridiculous".
"If this goes to a military solution, it's going to be tragic on an unbelievable scale", Mattis said.
The "relatively low compromise rate of South Korea, Japan, and the US runs contrary to every attack ever authorized by Pyongyang", reported Cybereason, a Boston-based security firm.More news: Trump decides against embassy move to Jerusalem
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Deputy North Korean Ambassador to the UN Kim In Ryong said that North Korea welcomes the idea of United States talks, but "what is important is not words, but actions", and that the USA needs to back off its hostile policy toward North Korea for the talks to have any value.
"The rolling back of the hostile policy towards DPRK is the prerequisite for solving all the problems in the Korean Peninsula", he said. "Therefore, the urgent issue to be settled on Korean Peninsula is to put a definite end to the U.S. hostile policy towards DPRK, the root cause of all problems".
Kim started the press conference praising the North's successful ballistic missile launch last weekend, which experts said demonstrated a significant technological jump - with the rocket flying higher and for a longer period of time.
Before an emergency meeting of the council Tuesday, U.S. Ambassador Nikki Haley declared: "You either support North Korea or you don't, but you have to choose". "Based on Pyongyang's goal of striking top enemies in their campaigns, it is highly unlikely that they would design a piece of malware that did not have a high probability of success against the U.S., South Korea and Japan".