One of the most enduring mysteries in United Nations history – the 1961 plane crash that killed Secretary-General Dag Hammarskjöld and all on board as he sought to broker peace in the Congo – will linger on, with a new assessment announced on Friday suggesting that 'specific and crucial' information continues to be withheld by a handful of Member States.

Mr. Hammarskjöld served as Secretary-General from April 1953 until his death aged 56, when the chartered Douglas DC6 aircraft he was travelling in with others, registered as SE-BDY, crashed shortly after midnight on 17-18 September 1961, near Ndola, then in Northern Rhodesia (now Zambia).