SANAA, Yemen -- Hundreds of thousands of anti-government protesters packed the streets of several Yemeni cities Wednesday to demand the president's ouster and denounce a munitions factory blast that left at least 100 people dead.Opposition groups have accused President Ali Abdullah Saleh of collaborating with al-Qaida militants by pulling back the army from the factory area and allowing the terror network to overrun the area.Read More... More on Ali Abdullah Saleh