GENEVA (Reuters) - North Korea does not want to start a nuclear war and the world is not seeking to overthrow its leader Kim Jong Un, the U.N. disarmament chief said on Tuesday. Izumi Nakamitsu, U.N. High Representative for Disarmament Affairs, said there was hope for a peaceful end to the tension  caused by the nuclear ambitions of North Korea, also known as Democratic People s Republic of Korea (DPRK).  I don t think DPRK wants to start a nuclear war,  she told a news conference in Geneva. On Monday, the U.N. Security Council unanimously decided to step up sanctions on North Korea after its sixth and largest nuclear test, prompting a war of words between diplomats at the Conference on Disarmament in Geneva.  Asked if the pressure on North Korea was pushing the world to the brink of nuclear war, Nakamitsu said U.N. officials were in touch with all sides and nobody - including North Korea - saw a military solution to the crisis.  That is just too catastrophic,  she said.  I think we all understand the consequences of a military escalation, a  military solution . That s why we keep saying that it would not be a solution for anyone, including DPRK.  She added:  Maybe I m missing something but as far as I hear, no one is really asking for any collapse of DPRK, quite the contrary. No one is talking about regime change, quite the contrary.  She was also hopeful that, as in the past, increased nuclear tensions might yield progress in disarmament talks.  When people say that because the international security environment is so difficult, tensions are so high, that we can t discuss disarmament, that is historically not accurate.  U.N. Secretary General Antonio Guterres has offered to play a role in mediating, as has Switzerland. So far no such steps have been taken, but the United Nations was prepared to get involved if asked to do so, Nakamitsu said.  We are definitely preparing ourselves, exploring scenarios as part of our normal contingency planning.  