The increase in rebel violence over the last few weeks has caused aid groups to cut back on aid deliveries. Drivers and aid workers are being threatened and shot at by the newly restive rebels. The threatened delay in food air deliveries has an impact on the rebels, as they often subsist on the food aid as well, taking a portion of donated food that passes through territory they control. If the rebels take too much (the excess is sold in the markets for money to buy other things), the aid groups halt the shipments. There is a constant state of negotiation between the rebels bands and the aid groups over how much food can be stolen while on its way to starving refugees.