The UN has called for a new push for nuclear disarmament amid concerns over the North Korean crisis and bilateral spats between Russia and the US. The threat posed by weapons of mass destruction continued and were also increasing, Secretary-General Antonio Guterres warned on Thursday, Efe news reported. He was speaking at the opening of a special Security Council session devoted to nonproliferation headed by Kazakh President Nursultan Nazarbayev. Kazakhstan, which voluntarily renounced the world's fourth-largest nuclear arsenal that it inherited from the former USSR, has made nuclear disarmament the main priority for the month it occupies the Council's rotating presidency. It coincides with new attempts to resolve the Korean crisis after years of erosion of international efforts to reduce the existing nuclear arsenals around the world. Global fears about nuclear weapons are at their highest point since the Cold War, Guterres said, calling the North Korean question the "most dangerous peace and security challenge in the world today". He said the consequences of a conflict would be "unimaginable". Nazarbayev offered his country as a venue for talks on the North Korean crisis, urged nuclear powers to give Pyongyang security guarantees as a way to get negotiations off the ground. The Kazakh leader said the 2015 nuclear pact with Iran was a "good example" for resolving complex issues via diplomacy. His proposals were on building confidence on disarmament, including making it more difficult for signatory countries to withdraw from the Nuclear Nonproliferation Agreement. It also aimed at an effective mechanism to prevent the acquisition of weapons of mass destruction. He called for eliminating "military blocs" and urged the creation of a system of guarantees whereby nuclear powers would make security commitments with non-nuclear nations. Guterres said that he wanted to "explore opportunities" to provide new impetus for disarmament and non-proliferation initiatives, efforts which have waned and required updating. During the session, Washington's UN Ambassador Nikki Hale hailed Kazakhstan as a "responsible member". She said "halting the nuclear proliferation might be more complicated now than in the past". Haley said Pyongyang's efforts to augment its nuclear arsenal was the greatest threat to the nonproliferation regime. She said Iran had violated its 2015 nuclear pact and become the "greatest cause of instability in the Middle East".