Kordofan lies within the boundaries of Arab-dominated northern Sudan but is home to the Nuba Mountains and the Nuba people, many of whom are Christian and fought alongside the southern rebels during the long north-south civil war. On July 9, southern Sudan is to formally declare its independence from northern Sudan, which many analysts say will leave the southern-allied militias in the north in a precarious position.

Late last month, the northern Sudanese Army warned that southern-allied militias still operating in the north should immediately disarm and that northern troops would soon be deploying across the states of Southern Kordofan and Blue Nile, both home to thousands of heavily armed, southern-allied fighters. Many diplomats at the time said that Kordofan was a tinderbox and predicted that if the northern army stormed in, a major conflict would break out, which is what seems to be happening.

United Nations officials said that while northern Sudanese warplanes bombed villages, northern forces were rolling in tanks and heavy artillery. In some areas, witnesses said, southern-allied militias are fighting back fiercely and possibly even preparing a major assault on Kadugli, the biggest town in Southern Kordofan.

Northern Sudanese officials have not denied the bombings and the use of overwhelming force, calling such tactics necessary to suppress a rebellion.

“Our purpose is to control the area, not kill the civilians,” said Al-Sawarmi Khalid, a spokesman for the northern Sudanese Army. He also said the conflict “may continue one week, two weeks, three weeks, one month, and also it may continue for some years.”

Church leaders and others are now likening Kordofan to Darfur, Sudan’s vast western region where government-backed militias killed thousands of civilians and displaced millions from their homes in the mid-2000s.

“The risk of another Darfur situation, with civilian populations at the mercy of government-supported terror, is a real one,” Archbishop Williams said in a statement on Tuesday.