FIGHTING could be heard in south Khartoum as envoys from Sudan's warring parties were in Saudi Arabia for talks that international mediators hope will bring an end to a three-week-old conflict that has killed hundreds and triggered an exodus. The U.S.-Saudi initiative is the first serious attempt to end fighting between the army and the paramilitary Rapid Support Forces (RSF) that has turned parts of the Sudanese capital into war zones, derailed an internationally backed plan to usher in civilian rule following years of unrest and uprisings, and created a humanitarian crisis. Saudi Arabia will allocate $100 million in humanitarian aid to…