LEWERE, Sudan » Children with shrapnel wounds lie in metal hospital cots. Thousands of others have been huddling in caves and stony riverbeds, fleeing the fighter jets and bombers prowling the skies. Villages are empty, fields unplowed. At the faintest buzz of a plane, people scatter into the bush, in a panic.

"Just lie flat, or you could get killed," warned Nagwa Musa Konda, the director of a local aid organization, as a plane growled closer.

Despite an agreement signed only days ago to bring peace to this part of central Sudan, it seems to be sliding inexorably toward war.

Young men here in the Nuba Mountains are being mobilized into militias, marching into the hills to train. All the cars in this area, including humanitarian vehicles, are smeared with mud to camouflage them from what residents describe as unrelenting bombings. And opposition forces vow to press their fight until they win some form of autonomy, undeterred by the government’s push to stamp them out.

"It’s going to be a long war," said Ahmed Zakaria, a doctor from the Nuba Mountains who recently quit his job to become an opposition fighter. "We want a secular, democratic state where we can be free to rule ourselves. Like Kurdistan," Zakaria said, smiling. "And we will fight for it."

The conflict is overshadowing one of the biggest events in the nation’s history: the independence of the southern part of the country and the creation of two Sudans. In just over a week, southern Sudan will officially break off from the north, the capstone of decades of civil war and years of international negotiations to stave off further bloodshed.

But the fighting in the Nuba Mountains, which sit in the north’s territory, underscores how fractured Sudan will remain. The same demands being espoused by opposition fighters here have been the kindling for major conflict — and major suffering — in several other corners of northern Sudan, where the government is determined to keep a firm grip across a country of diverse groups clamoring for their rights.

In the few towns in this vast landscape of terraced mountainsides and thatched-roof villages, the northern government has been amassing tanks, rocket launchers, artillery and thousands of soldiers and allied militiamen, either to pressure Nuba leaders into disarming or to prepare for a major offensive once the rains stop in a few months.

While the hillsides are slick and muddy, the government can do little but bomb, as it acknowledges doing. But government officials say their fight is solely with opposition fighters, not with civilians, contending that widespread reports of civilian casualties are fabrications intended to rally Western nations against Sudan.

"The government is trying to control and take care of the people for peace and security and actually defeat and remove all the traces of rebels from the area," said Rabie A. Atti, a government spokesman. "We are not against the people."

But as the conflicts in the western region of Darfur and southern Sudan long before that have proved, counterinsurgencies often cast a wide net.

At a small, mountainside hospital here in Lewere, an entire ward is filled with victims who said they were at a well, fetching water, when they were bombed. Most are children. Their whimpers filter through the mesh windows, along with the pungent smells of antiseptic solution and decaying flesh.

Inside, Winnasa Steven, a 16-year-old girl, writhed on a cot. Out of her hip, doctors cut out a 3-inch chunk of ragged shrapnel, which her mother keeps, wrapped in white paper.

"I am in big pain," Winnasa said.

Next to her, a toddler cried, his face a map of bandages. Not far away, a little girl sucked down spoonfuls of porridge. Her mother tried not to look at the gaping hole in her leg.

Tensions had been building steadily in the Nuba Mountains since a disputed election in May. The governing party’s candidate, Ahmed Haroun, who has been indicted on charges of war crimes in Darfur by the International Criminal Court, won the governorship of Southern Kordofan, the state that encompasses the Nuba Mountains, by a margin of 6,500 votes out of 400,000, defeating a popular Nuba leader who used to be a guerrilla fighter.

The Carter Center endorsed the election, but people here cried foul, saying the government had fiddled with the tallies because Southern Kordofan was too important to lose. It has the most productive oil fields in the north and borders the south, making it a useful rear base for the militias widely believed to be armed by the north. Kordofan also has fertile land, minerals and gum arabic, an ingredient in countless Western products.

This area has a history of oppression — and resistance. The Nuba people were enslaved by their neighbors hundreds of years ago, bombed by the British and subjugated by the north. The people here are not Arab like the northerners, and many are Christian. Tens of thousands of Nuba fighters joined southern rebels during the north-south civil war. It is these southern-allied fighters who are refusing to disarm, and clashes erupted in June.

In Kadugli, the biggest town in the Nuba Mountains region, many witnesses say the Sudanese Army and allied Arab militias have gone house to house, methodically executing civilians. Kamil Omer El Amin, a Nuba agricultural officer, matter-of-factly described what happened to his friend Philip.

"He drove up to the U.N. compound," Amin said. "The intelligence agents told him to get out of the car. He sat down. They shot him in the chest."

U.N. officials confirmed the killing but said the overwhelming number of northern troops rendered them powerless to stop it, even though the shooting happened outside the U.N. base.

Many Nuba professionals have fled to the opposition-controlled mountaintops.

"We spent two weeks up there, drinking something you can barely call water," said Caddy Ali, who worked for a project financed by the World Bank.

Ali said the agreement signed Tuesday between southern-allied opposition leaders and the government, which outlined steps for political compromise and a cease-fire, was meaningless.

"We’re never going to forgive them now," she said. "Do you know how many people I’ve seen die right in front of me?"

Aid workers said hundreds of civilians had been killed in the bombings. The Sudanese Army is also blockading roads and bombing airstrips, essentially cutting off food supplies.

"These people are going to starve," one Western aid worker said.

On Thursday, a group of Nuba aid workers stopped their car to pick up some deleib, a wild mushy fruit that looks like a coconut.

"This is what the fighters lived off in the 1990s," Zakaria said.

It seems some people are preparing to live off it again.

© 2011 The New York Times Company