D. Commencement of the commission’s/ mission’s work Commissions/missions are usually set up in response to allegations of serious violations of international human rights law or international humanitarian law that require urgent reaction, and in most cases they work under very tight timelines to complete their assessments and report back to the mandating authority. However, there is usually a temporal gap between agreement on the mandate (for example, in the form of a United Nations resolution), the appointment of the members, the establishment of the commission/mission and the actual commencement of its work. Appointing members and securing their availability over the required period is a process that may stretch over weeks or even months in the most difficult cases. At the same time, and often while this appointment process is still under way, OHCHR needs to set up a secretariat and make all the administrative arrangements required for the operation of the commission/mission. These activities are carried out under considerable time pressure, and at times uncertainty about the final financial allocations, and require effective coordination and quick action by several parts of OHCHR. It is essential that the coordinator and key secretariat staff be identified, appointed and/or recruited as soon as possible so as to be able to start preparations for the work of the commission/mission. It has been OHCHR practice for the secretariat to be in place at least two weeks before the commission/mission convenes. Commissions/missions have been based variously in Geneva, in the country concerned, or in both. The decision of where the commission/mission will be based depends on a number of factors, including security, access, cooperation afforded by the country concerned, logistics, costs and United Nations presence in the country. If the commission/ mission is based in Geneva, field missions to the country concerned or other countries where information relevant to its mandate may be available are a normal part of its work. The mandate (as set out in resolutions or, for commissions/missions established by the Secretary-General or the High Commissioner, in terms of reference) specifies the time frame within which the commission/mission must complete its work and submit its report to the mandating authority. The official date of commencement of the work of the commission/mission may be different from the date at which the establishment of the body is announced, and is usually the date on which the members first convene, usually in Geneva, to discuss and agree on the commission’s/mission’s programme, terms of reference and methods of work. 30 COMMISSIONS OF INQUIRY AND FACT-FINDING MISSIONS ON INTERNATIONAL HUMAN RIGHTS AND HUMANITARIAN LAW