The popular uprising against the government of Gaddafi began in January 2011 as non-violent protests, simultaneously with other protests in the Arab Spring. Within weeks, violence broke out in clashes between police and protesters. In February, the National Transitional Council (NTC) was formed in an effort to consolidate efforts for change in the rule of Libya. Gaddafi forces lost control of several cities in eastern Libya, and a number of officials resigned or defected from his government. In March, Gaddafi forces launched a counteroffensive, and regained many of the cities that had been lost to opposition forces. In mid-March, tanks of Gaddafi forces rolled into the main remaining bastion of the opposition forces, Benghazi. At the same time, aircraft of the French Air Force entered Libyan airspace under the mandate of United Nations Security Council Resolution 1973, to prevent any attacks on the city. A multinational coalition launched a large scale air-based military intervention to disable the Gaddafi government's military capabilities and enforce the UN Security Council resolution. By the end of March, command of the coalition operations had been assumed by NATO under Operation Unified Protector.