AL-FASHAGA, Sudan — The bodies floated over the border in ones and twos, bloated and bearing knife or gunshot wounds, carried on waters that flow from the Tigray region of northern Ethiopia.
At least 40 bodies have washed up on a riverbank in eastern Sudan in the past week, in some cases just a few hundred yards from the border with Ethiopia, according to international aid workers and doctors who helped retrieve the corpses.
The grisly finds at the river are apparent evidence of the latest atrocities in a brutal, nine-month civil war between Ethiopian federal forces and their allies, and fighters in the Tigray region of northern Ethiopia — a conflict accompanied by reports of massacres, ethnic cleansing and widespread sexual assault.
Few of the bodies have been identified, but several contained tattoos that suggested they were ethnic Tigrayans, and many bore signs of a violent death or had their hands bound behind their backs, witnesses said.
“They were terribly injured, and some were riddled with bullets,” said Tewodros Tefera, a surgeon with the Sudanese Red Crescent Society, a humanitarian group, who works in a refugee camp beside the border.
Dr. Tewodros, who himself fled Ethiopia for Sudan at the start of the war in November, said in a telephone interview that he personally had buried two bodies pulled from the Sitit River (known as the Tekeze River in Ethiopia) near the village of Hamdayet, on Sudan’s border with Ethiopia.
The surgeon said the bodies had come from the direction of Humera, an Ethiopian town on the river six miles upstream, which has become a recent focus of the intensifying war between Tigrayan forces and those allied with Ethiopia’s prime minister, Abiy Ahmed.
The killings came to public attention on Monday after images of grotesquely bloated bodies floating in the river circulated on social media, recalling the horrors of the genocide in the East African nation of Rwanda in 1994, when the bodies of victims also flowed over an international border.
Ethiopia’s government denounced the pictures appearing this week as fakes, orchestrated by its Tigrayan foes to discredit Mr. Abiy.
Mr. Abiy, who won the Nobel Peace Prize in 2019, has faced a stream of reports of atrocities committed by Ethiopian troops and their allies in Tigray in recent months. His government has hit back with claims that the Tigrayans have also committed abuses, including recruiting child soldiers to their cause.
In a text message, Mr. Abiy’s spokeswoman, Billene Seyoum, referred to a government statement from July 22 that appeared to anticipate the controversy, accusing Tigrayan forces of dumping in Humera the bodies of 300 people who had been killed in other parts of Tigray in an effort to generate “made-up propaganda of a massacre.”
A senior official with an international aid organization, however, confirmed that 40 bodies had been pulled from the river near Hamdayet, and broadly supported the accounts given by Dr. Tewodros and two other refugees at the camp. The official requested anonymity to avoid imperiling his organization’s relationship with the Ethiopian authorities.
The gruesome spectacle highlighted how the accelerating conflict in Tigray, where at least 400,000 people are living in famine-like conditions, is spreading to other parts of Ethiopia and even across the country’s international borders.
In recent weeks fighting has raged in Ethiopia’s neighboring Afar region to the east of Tigray, displacing thousands of civilians, as Tigrayan fighters seek to pressure Mr. Abiy’s government by trying to cut off the country’s most important supply route.
Friction is also mounting between the Ethiopian government and international humanitarian agencies trying to stave off famine in Tigray. On Tuesday the Dutch arm of the aid agency Doctors Without Borders said Ethiopia had suspended its work in Tigray and three other regions of Ethiopia for three months.
In the capital, Addis Ababa, the visiting United Nations humanitarian chief Martin Griffiths said Ethiopian accusations, made last month by a cabinet minister, that international aid groups are aiding the Tigrayan rebels, were “dangerous.”
In western Tigray, tensions have been rising as the pro-government forces that control the area — ethnic militia fighters from the neighboring Amhara region of Ethiopia and allied soldiers from the country of Eritrea, to the north — gird for an expected Tigrayan assault.
The Tigrayans, known as the Tigray Defense Forces, have been threatening to attack western Tigray since they won a series of battles in late June, including the recapture of the provincial capital, Mekelle.
In Humera, Amharan and Eritrean forces have dug trenches, amassed military equipment and detained local civilians they accuse of helping the Tigrayan forces, according to refugees and aid workers.
Amhara militia fighters, known as the Fano, have ordered ethnic Tigrayan residents to leave, several refugees said. The number crossing the border into Sudan has increased fivefold to about 50 a day, the aid official said.
“They are walking from house to house, intimidating people,” said one of those refugees, Filmon Desta, 23, in a video interview over WhatsApp. “It’s obvious that it’s ethnic cleansing.”
At the same time, the bodies have been floating across the border. Nine corpses have been pulled from the water near Hamdayet, and another 29 from a village 45 miles downstream called Wad al-Helew, Dr. Tewodros said.
Two victims were identified by Tigrayans who knew them, and two others had tattoos in the Tigrinya language.
The bodies that floated over the border this week washed up on the northern edge of al-Fashaga, a triangle of land that has been the subject of a border dispute between Ethiopia and Sudan for over a century.
After years of intermittent clashes, the dispute flared late last year after the Ethiopian troops that controlled much of al-Fashaga suddenly left to fight in Tigray. Weeks later, Sudanese troops went on the offensive and captured a large swath of the disputed territory.
Sudanese officials said they launched the attack in response to months of violent incursions from inside Ethiopia, which killed dozens of Sudanese civilians.
In a rare visit to al-Fashaga by a Western reporter earlier this summer, military officers, community leaders and local farmers told how a longstanding territorial dispute had erupted into a serious cross-border confrontation.
The New York Times saw trucks of Sudanese soldiers laden with weaponry and food rations hurtling toward the front line. Hundreds of Sudanese soldiers were stationed in Barakat Nurein, a village that was occupied by Ethiopian farmers until Sudanese forces snatched it in January.
At a line of recently dug graves, Omer Adam, a local farmer, said his 25-year-old daughter was among six people who had been shot dead by Ethiopian forces while working the fields.
“We found her dead on the spot,” he said, standing over a mound marked with a pile of dried twigs. “A bullet entered her chest and came out through her back.”
United Nations officials estimate that dozens of civilians have also been killed inside Ethiopia as part of the fight over al-Fashaga, but there are no official tallies. Ethiopia’s Foreign Ministry did not respond to questions about the dispute.
The dispute, one of numerous challenges confronting Mr. Abiy, has the potential to be a “detonating point for the region,” said Jonas Horner, an analyst with the International Crisis Group, a conflict research body.
Among the bodies that washed up in Sudan recently was that of a woman identified as Feven Berha, a resident of Humera.
Awet Yiscer, a refugee, said Ms. Feven had gone missing from Humera in late July. Three days later, her body turned up in Sudan with both eyes missing. As word of her death spread, scores of Tigrayans fled over the border into Sudan.
“I can’t even begin to express the situation,” said Mr. Awet, who fled his home recently after 40 years. “These are very dark days.”