An eight-month-long civil war in Sudan escalated Monday as the country’s so-called Rapid Support Forces appeared to solidify their advance on Wad Madani, a city southeast of the capital, Khartoum. The city has taken on an outsized importance in recent months as a hub for humanitarian operations that are now imperiled by the rebels’ attack.

Fighting intensified as the RSF overran Wad Madan on Friday, leading the UN’s humanitarian agency to suspend aid “until further notice” to the state of Gezira, where nearly half a million displaced people have found refuge since the war broke out.

The developments have alarm bells ringing at Foggy Bottom. On Saturday a spokesman for the Department of State, Matthew Miller, said Wad Medani “has become a safe haven for displaced civilians and is an important hub for international humanitarian relief efforts. A continued RSF advance risks mass civilian casualties and significant disruption of humanitarian assistance efforts.”

“We are also deeply concerned by reports of renewed fighting in the northeastern suburbs of El Fasher on December 16, including credible reports that several internally displaced persons were injured by stray gunfire,” Mr. Miller said in a statement, adding, “We urge the RSF to immediately cease their advance in Gezira State and refrain from attacking Wad Madani.”

Given the turmoil in Sudan, those words are likely to fall on deaf ears.  Since April, forces loyal to the army chief, Abdel Fattah al-Burhan, have been at war with RSF paramilitary forces commanded by his former deputy, Mohamed Hamdan Daglo. Mr. Dagalo is also known as Hemedti, or “little Mohammed,” and was previously a fighter in the feared Sudanese Arab Janjaweed militia, which came to international attention because of its link to atrocities in the Darfur conflict. The renegade general is said to command tens of thousands of troops.

The war that broke out on April 15 has already left more than 12,190 dead, according to an estimate from the NGO Armed Conflict Location & Event Data Project, and the figure is considered largely underestimated. There have been waves of deadly violence in Darfur, and vast portions of Khartoum are in ruins.

According to the UN, more than 5.4 million people have been displaced and about 1.3 million have fled abroad.

There are also indications that Kremlin-backed mercenary forces helped whip up the violent power struggle last spring. Some of those forces, identified with the Wagner Group, operated near the border with the Central African Republic. Moscow is currently attempting to rebrand those operatives as part of a new Africa Corps, the French newspaper Le Monde reported. 

In the meantime, the RSF has posted videos showing its fighters in pickup trucks driving along the streets of Wad Madani and over a bridge across the Blue Nile. In one video, Reuters reported, RSF fighters carrying rifles stood with their arms around Coptic priests, who said they had not been able to flee.

According to regional press reports, the RSF said its attack on Wad Madani was a pre-emptive move to thwart the Sudanese army’s use of the area as a launching pad for an offensive — while the army said the attack underscored the paramilitary’s intent to kill civilians and loot their property.

Although the smoke has yet to clear following the RSF’s onslaught, a wider humanitarian crisis looms as relief efforts appear to be on hold and Sudan has already been facing a hunger catastrophe. Wad Madani is Sudan’s second largest city and is situated in an agriculturally important part of the war-torn country.