BENTIU — When an armored truck rumbled into her village in the summer of 2014, Betty Sunday froze. The militiamen jumped out of the vehicle, weapons in hand, and began bursting into homes. Some of the soldiers looked well shy of 16 years old. The gunshots rang out, and women screamed. Betty does not know how many were raped.

"I fled into the bush with my son and husband," she recalls.

This began a month of wandering with others who had fled, where surviving meant eating whatever you could find.

"The men were going into neighboring villages to steal food," she recounts. "One day, my husband left to search for food. He never came back." Betty's voice grinds to a halt. She is silent, trying to hold back tears. "Deep within me, I knew that he had died."

This took place near Wunduraba, a small village 100 kilometers from Juba, the capital of South Sudan, but such stories are recounted by countless men and women, citizens of the youngest state of the world, consumed by conflict since its birth in 2011.

The Juba Hospital treats infants in a state of severe malnutrition. It is also a place of refuge for women, many of whom find themselves alone and without resources when their husbands take up arms.

The famine that so far has touched the most vulnerable, is now arriving at the urban middle class.

In February, famine was declared in northern regions of the country, with some 100,000 people directly affected. Many have already died. In March, the United Nations said some 20 million people in Yemen, Somalia, Nigeria and South Sudan faced famine, the worst such crisis since World War II.

In total, more than six million South Sudanese require emergency food aid. Such conditions are usually the result of a bad harvest or drought. But this humanitarian disaster has a specific human cause. The country's civil war has thrown millions of people out of their homes, destroyed crops and largely wiped out the economy. With an inflation rate up to 600%, the most basic goods are priced out of reach of most citizens. The famine that so far has touched the most vulnerable, is now arriving at the urban middle class.

The Juba hospital specialized in infant malnutrition is overcrowded with mothers and their starving children. That is where we met Betty Sunday, who has been living on a hospital bed near her daughter for four days. At 17 months, the girl barely weighs more than 5 kilograms (11 pounds), half the normal weight. For the last six months, her mother had only fed her a serving of milk every other day, which cost nearly all the 50 cents she earns a day from washing dishes at a nearby home.

"One morning, I was preparing breakfast outside," she recounts. "When I went back inside, I thought that my little girl was sleeping. But then I realized she was unconscious, and ran her to the hospital."

Dozens of woman wait under a tent erected at the entrance of the Juba hospital for infants to be examined by a doctor. In the alleys of the Bentiu camp for displaced people, children are everywhere. Forty percent of the total population of the camp is under the age of 5.

To collect firewood for cooking and construct the huts for heating, people take the risk of venturing out of the camp secured but the UN. The displaced people bathe, do their laundry and wash dishes in polluted water. By last month, more than 6,000 cases of cholera, including 172 deaths, had been recorded in the country since the outbreak of the epidemic in June 2016.

Also in the Bentiu camp, UNICEF has opened four schools that welcome several thousand children each day. Each week, between 25 and 30 children are born in the camp's hospital, also run by the UN agency after it was ransacked in 2014 by local militiamen.

The malnutrition unit at the Juba Hospital is overflowing. The makeshift curtains fixed on the edges of the windows filters out some exterior light, but does little to reduce the suffocating heat of this late morning.

On three rows of battered-looking beds, women give bottles to their children who no longer have the strength to feed themselves. Certain cases are particularly grave. At 18 months, Linda barely weighs 5.3 kg (under 12 pounds). The day before, she had weighed 200 grams more. The doctors can't stop her diarrhea.

"It's because she is HIV-positive," explains Betty Achan Ocheny, the nutritionist who supervises the service.

In this country, war and famine are inextricably tied. The first is the cause of the second. Founded on Christian and animist southern lands of Sudan, South Sudan proclaimed its independence in 2011. But clashes began in 2013, prompted first by political power plays, but soon fueled by ethnic strife. The Dinkas are the majority ethnic group from which the president comes and who stand in opposition to the Nuers, the group from which the deposed vice president comes. The fighting is concentrated in the north of the country in the cradle of the rebellion, the Unity State region, which is, essentially, Nuer.

"When the army enters the village, they speak to the civilians in the Dinka language. Those who cannot respond are killed on the spot."

The government military forces, the Sudan People's Liberation Army is largely composed of the Dinkas, and is increasingly accused of atrocities, particularly against Nuer civilians of the Unity State. The conflict has prompted more than 1.5 million civilians to flee into neighboring countries, and nearly 2 million are displaced inside the country. In total, more than one third of the population (around 11.3 million people) has been chased from their homes by the war.

The ethnic dimension of the conflict creates fears of a new Rwanda. In March, a UN report alerted to the risk of genocide, with the Dinka-majority government forces accused of carrying out systematic attacks against civilians on the basis of their ethnicity.

"The Nuers are deliberately targeted," assures Kidega, a local humanitarian and Nuer himself. "When the army enters the village, they speak to the civilians in the Dinka language. Those who cannot respond are killed on the spot."

And in some cases, the soldiers themselves do not even need to speak to them to know. Certain Nuers have their origin engraved on their skin: six deep horizontal scars on the forehead. A traditional scarification that marks the passage from adolescence to adulthood. Having grown up and studied in Khartoum, before the independence of South Sudan, Kidega, does not have them.

"I'm lucky for that, because it has really gotten too dangerous here," Kidega says. "The government treats our people like foreigners, not even as sub-citizens."

Priti Patel, the British secretary of state of international development, is uncompromising. "It is tribal, it is absolutely tribal, and so on this basis, it is genocide," she declared after a visit to South Sudan last month.

The humanitarian aid workers permantly posted in the region are more cautious about the characterizations. "The notion of genocide returns to a very precise juristic definition," says one western official. "At this stage, we do not have formal evidence that a methodical plan of elimination of a people on the basis of ethnicity exists."

Moreover, the Dinkas do not have the monopoly over the ethnic-driven atrocities. Violent acts committed by the Nuer militiamen are less documented, but very real. In May 2014, rebels loyal to former Vice President Riek Machar killed more than 200 people in Bentiu.

Right now, the most urgent concern is hunger. In anticipation of the rainy season, the World Food Programme has stocked 18,000 tons of sorghum, the cereal that constitutes the basic diet of the South Sudanese. For the moment, at the Bentiu camp, there is calm among the population.

"But the situation is very volatile. The battles can resume at any time," warns Francis Sarpong Kumankuma, the World Food Programme's local representative. "Our work must be done quickly. When the mud comes, the road are unpassable."