Somalia's transitional government has offered a general amnesty to insurgent fighters in Mogadishu who surrender and promise to renounce violence. The decision made by the Cabinet over the weekend was announced Tuesday and comes after Al-Shabaab retreated from the capital, Mogadishu, early Saturday. The al Qaeda-linked group has been waging an insurgency against Somalia's transitional government since 2006. In confirming that Al-Shabaab fighters had left the city, spokesman Sheikh Ali Mohamud Rage said the fighting was hardly over. "The reasons we withdrew from Mogadishu is we have made changes in our tactics of war," he told the group's radio station, Andalus. "We withdrew because we want to save lives of the poor civilians, but we will launch operations against government (and African Union) forces in the coming hours." Some observers said they believe the Islamists withdrew because of funding woes and drought-related issues. The United Nations has declared famine in five areas of southern Somalia, including Mogadishu. In all, about 12 million people in the Horn of Africa region need assistance. Somalia is the worst hit. "The immediate priority must now be to focus on the humanitarian situation and I call on all parties, from the donor community to all parts of the Transitional Federal Government, to do everything possible to ensure and facilitate the immediate delivery of assistance to those most in need," U.N. special representative Augustine Mahiga said. Al-Shabaab has called the famine a "crusader" invention and an excuse for occupation, and issued threats to aid agencies delivering food to afflicted areas. As crops withered, thousands of people fled and livestock starved. But the militants kept their ban on aid groups operating in their territory in southern and central Somalia and parts of the capital.