This article has been corrected to reflect that fact that the recent attack on Bor was said to be the work of pro-government forces, not rebels.

There is no body count for the city of Bentiu in South Sudan, perhaps because there are too many to count. The news from the United Nations’ mission in South Sudan only describes “piles and piles” of bodies. Other reports speak of streets “littered” with bodies. A mosque was filled with hundreds of bodies. More inside the Catholic church. Bodies in the hospital.

“A strong stench of decomposing remains filled the air, while vultures and dogs ate off limbs, scalps and abdomen flesh,” said one report.

There are so many that they’re being collected by bulldozers and dumped into mass graves, the White House said last night.

“Accounts of the attacks shock the conscience,” said a statement Tuesday night from the White House press secretary. It’s an “abomination.”

Bentiu is the capital of the South Sudanese state of Unity, routinely described as “oil-rich.” But to call it “rich,” and, indeed, to call the state “Unity,” seems absurd — and the tragedy has pushed South Sudan, the youngest country in the world, into yet another chapter of violence.

Born in 2011, South Sudan came to be with the help of the United States out of the rubble of a Sudanese civil war. A split between President Salva Kiir and rebel leader Riek Machar triggered fighting between their forces in December. Since then, an estimated 1 million people have been driven from their homes, about 800,000 of them internally displaced and another 200,000 refugees driven into into Kenya, Uganda, Ethiopia and Sudan.

But these killings were, in some ways, different from those that have come before. The rebels made no secret of their plans. A local radio station featured rebel commanders warning certain ethnic groups, everybody but the Nuers, that they were coming for them, calling on the other groups to rape the non-Nuer women.

People had sought refuge in places of worship and healing. But as has been the case in other towns, there wasn’t any after the killing began on April 15.

The killers, identified by the United Nations as forces of the Nuer-led “Sudan People’s Liberation Movement in Opposition Army” led by former vice president Machar, went from place to place, from mosque to church to hospital, separating people by ethnicity and religion and shooting the ones left behind.

The people spared were mostly from the Nuer community. But not all of them made it. Some Nuers who hid were shot, too, according to reports. “Several Nuer men, women and children were killed for hiding and declining to join other Nuers who had gone out to cheer” the rebel forces, said the U.N. report after the killings.

“It’s the first time [in South Sudan] we’re aware of that a local radio station was broadcasting hate messages encouraging people to engage in atrocities,”  the United Nations’ Toby Lanzer, who was in Bentiu on Sunday and Monday, told the AP by phone. “And that really accelerates South Sudan’s descent into an even more difficult situation from which it needs to extract itself.”

As bad as things have been, they could get worse.

Lanzer reported that thousands of civilians from several ethnic groups streamed to the U.N. peacekeeping base in Bentiu because many believe more violence is coming. “The base now holds 22,000 people — up from 4,500 at the start of April — but can supply only one liter of water per person per day. Some 350 people must share one toilet.”

“The risk of a public health crisis inside our base is enormous,” he said.

Raphael Gorgeu, head of Doctors Without Borders in South Sudan, agreed. People will die in the base in the coming days, he predicted. If they don’t die from sickness, they may be killed.

In February, a hospital where Doctors Without Borders was working in South Sudan was attacked by armed men. The doctors and nurses had to flee. When they returned, “there were 11 dead bodies in the hospital — patients murdered in their beds,” Carlos Francisco, the organization’s field coordinator in the town of Malakal, told wire services. “We found three more bodies near one of the hospital gates.”

The civil war has conferred no immunity on the United Nations, either.

On April 18, pro-government “armed civilians” attacked the U.N. base in Bor. “At the time of the attack, there were some 5,000 displaced civilians in a protection-of-civilians site (POC) inside the base. A yet to be confirmed number of these civilians were killed or wounded by these assailants who came under the guise of peaceful demonstrators intending to present a petition,” said a U.N. statement.

Rebel spokesman Lui Ruai Koang dismisses accusations as “unfounded, cheap propaganda.”