Liu Jieyi (C, front), China's permanent representative to the United Nations, speaks during an open debate of the UN Security Council on "non-proliferation of weapons of mass destruction", held at the UN headquarters in New York, Aug. 23, 2016. UN Secretary-General Ban Ki-moon on Tuesday stressed the need to seriously refocus attention on nuclear disarmament, and called for the eradication of the weapons of mass destruction "once and for all." (Xinhua/Li Muzi)