Carnage continues in the Sudan: Two weeks after Colin L. Powell and Kofi Annan visited this part of Sudan in the hope that the glare of diplomatic shame might arrest a human crisis, conditions are still miserable. Days after the American secretary of state and the United Nations secretary general ended their tour, witnesses said, gunmen stormed a girls' school in the desert region of Darfur, chained a group of students together and set the building on fire. The charred remains of eight girls were still in shackles when military observers from the African Union arrived on the scene. That is a gruesome reminder of the kind of violence that the Sudan government has promised to stop by reining in the Janjaweed militias that it once encouraged when the government's focus was on quelling a civil war that swept Darfur. But since the visits, killing and raping continues, and health conditions are more dangerous. The government has promised to rein in the militias and is offering a show of force, sending in police officers who were on display here during a visit, lined up in formation and marching in place. But the Arab militias have continued to drive the African residents of Darfur from their villages, although aid workers say the rate may have slowed. What progress there has been is hard to determine in a region that is so vast and inaccessible. Even if the marauding and killing can be controlled, sickness and starvation are taking their toll. There is now the threat of an epidemic that could cause more deaths than the months of violence. In the deaths from illness, many are like the two children whose hearts recently stopped beating as Dr. Jerry S. Ehrlich held them in his arms. Both were chronically malnourished, sapped of their strength over time. "We're trying to save as many kids as we can," said Dr. Ehrlich, a New Jersey pediatrician working for Doctors Without Borders at the sprawling Kalma camp outside Nyala.