GOMA, Congo (AP) - Pledges from six nations and their rebel allies to pull back forces in war-ruined Congo were put to the test Thursday, with Rwanda the first to say it had started withdrawing from key battle zones. Thursday's U.N.-monitored disengagement deadline is a key test to a long-stalled cease-fire for Congo, which has seen its mineral-rich territory carved up and 2 million of its people sent fleeing by the 2 1/2-year civil war in the heart of Africa.