A/71/755 2/15 17-00808 I. Background 1. On 21 December 2016, the General Assembly adopted resolution 71/248, by which it decided, in paragraph 4, to establish the International, Impartial and Independent Mechanism to Assist in the Investigation and Prosecution of Persons Responsible for the Most Serious Crimes under International Law Committed in the Syrian Arab Republic since March 2011. 2. By that resolution, the Secretary-General was requested, with the support of the Office of the United Nations High Commissioner for Human Rights, to develop the terms of reference of the Mechanism within 20 working days of its adoption, i.e. by 20 January 2017. The Assembly also requested that the steps, measures and arrangements necessary for the speed...