UN officials warn the so-called "no fire zone" in Sri Lanka, a nearly 14-square-mile area along the northeast where civilians are trapped between the rebel Tamil Tigers and advancing government forces, is in danger of becoming a humanitarian catastrophe. Civilians trapped there cannot stay for fear of being shelled by the government, but they cannot run for fear of being shot by the rebels. While scarce water and medical supplies are dwindling, UN officials have been fearful to directly criticize the Sri Lankan government as they expect the government might expel aid groups in response.