Fatima is losing count of the number of drone attacks on the besieged city of El Obeid in Sudan, but says the attacks this past weekend were the most violent so far.

The drones hit schools and fuel stations, killing more than 20 people, including students, she says. “Over the past few months, seeing 40 or 45 drones is the norm. You can literally count them,” said the aid volunteer, whose name has been changed for fear of retribution.

El Obeid, a city of half a million people, is a key battleground in the war between the Sudanese Armed Forces (SAF) and the paramilitary Rapid Support Forces. Attacks mounted by the RSF have prompted the UN and other agencies to warn of the risk of atrocities.

Located between RSF-held areas in the western Darfur region and army-controlled regions in the east, El Obeid has suffered repeated drone strikes on its infrastructure. The army is fighting to stop the paramilitary group setting up another blockade after a siege in February last year.

At least 45 people were killed and 41 injured in 15 drone strikes in the city and surrounding areas from 6 June to 28 June, according to the UN human rights office. There are growing fears of a repeat of the massacre in the city of El Fasher last year, when RSF fighters went on a rampage after capturing the city at the end of an 18-month siege.

Amnesty International released a report on Wednesday saying the RSF had committed ethnic cleansing and crimes against humanity in its campaign to capture El Fasher. An independent fact-finding mission for the UN had already said the RSF’s seizure of the city showed the “hallmarks of genocide” against non-Arab communities.

On Friday, Volker Türk, the UN high commissioner for human rights, addressed delegates in Geneva during an urgent debate called by the UK and backed by Germany, Ireland, Norway and the Netherlands.

He said: “The ‌signs from El Obeid are ‌clear and unmistakable: another human rights catastrophe is unfolding in Sudan.

“This is not a drill. It is a red alert that needs to land on the desks of heads of state and government around the world. Their phones should be running hot in the coming days and weeks, with ideas on how to prevent atrocity crimes in El Obeid and in other places in Kordofan.”

El Obeid hosts an SAF infantry division and an airbase, in addition to about 100,000 refugees displaced by violence.

Experts have highlighted significant concentrations of RSF troops around the city and warn of an imminent ground offensive.

A report released on Monday by the Yale Humanitarian Research Lab found damage to electricity generation, fuel storage facilities and the main market that was “consistent with intentional bombardment of civilian infrastructure necessary for the sustainment of life”.

It said the SAF has constructed about 30 miles (50km) of defensive positions – suggesting it expected a siege.

Nohad Eltayeb, a senior research assistant at the Acled conflict monitoring group, said it had recorded 27 drone strikes last month around El Obeid, the highest monthly total since the start of the conflict in 2023.

In a diary voice note for the Avaaz human rights advocacy group, Fatima spoke of living life on the edge because of drone attacks on hospitals, fuel stations and other facilities. An attack last week struck the city’s main power station, causing blackouts in most of the city, she said. Drones have also hit people gathering to share Starlink internet connections when telecommunications networks are down, she added.

“I cannot begin to describe how terrible the situation is right now,” Fatima said. “Even the way people talk at funerals is different. Instead of praying for the deceased, they would be talking about how they died.”

According to Fatima, merchants have increased prices, saying their goods are targeted by drones on the way to El Obeid from other parts of the country or simply looted.

Ahlam, a humanitarian worker whose name has also been changed, said residents had become accustomed to pain, loss and fear from constant drone attacks. “In just the past two weeks, nearly every essential service and piece of critical infrastructure has been hit,” she said.

She added that some people had considered leaving the city, but attacks on fuel stations had driven up prices, making transport much more expensive. She fears devastating consequences if the conflict escalates, noting the already huge number of displaced people in the city.

Will Davies, Sudan director at Avaaz, said the drone attacks had created an “extremely dire” situation in El Obeid. He said the city lacked the ethnic dynamics that were a factor in the El Fasher killings and there was unlikely to be a major ground offensive because “the evidence isn’t there in terms of a force big enough to do it”.

Mohamed Badawi, director at the African Centre for Justice and Peace Studies, called for a ceasefire and for the international community to push for the creation of safe corridors for people to flee El Obeid.

The war began in April 2023 when a power struggle between the SAF headed by Gen Abdel Fattah al-Burhan and the RSF led by Gen Mohamed Hamdan Dagalo erupted in violence in the capital, Khartoum.

The fighting has killed hundreds of thousands of people and displaced many more. It has been fuelled by foreign powers with vested interests who are supporting sides in the conflict.

On Monday, the Raoul Wallenberg Centre for Human Rights and a coalition of civil organisations referred high-level officials based in the UAE, Iran, Turkey and Egypt to the international criminal court “for aiding and abetting atrocity crimes” in Darfur. They accused them of supplying arms, mercenaries, equipment, financing and logistical support.