Operation Unified Protector was an NATO operation enforcing United Nations Security Council resolutions 1970 and 1973 concerning the Libyan civil war and adopted on 26 February and 17 March 2011, respectively. These resolutions imposed sanctions on key members of the Gaddafi government and authorized NATO to implement an arms embargo, a no-fly zone and to use all means necessary, short of foreign occupation, to protect Libyan civilians and civilian populated areas. The operation started on 23 March and gradually expanded during the following weeks, by integrating more and more elements of the multinational military intervention, which had started on 19 March in response to the same UN resolutions. As of 31 March 2011 it encompassed all international operations in Libya. NATO support was vital to the rebel victory over the forces loyal to Gaddafi. The operation officially ended on 31 October 2011, after the rebel leaders, formalized in the National Transitional Council, had declared Libya liberated on 23 October.