The United States on Tuesday accused a Sudanese paramilitary group and its proxies of committing genocide, singling them out in a conflict of unchecked brutality and drawing fresh attention to the scale of atrocities being perpetrated in Africa’s largest war.

Secretary of State Antony Blinken said the Rapid Support Forces, the paramilitary group fighting against Sudan’s military, had committed acts of genocide, including a fearsome wave of ethnically targeted violence in the western region of Darfur.

The Treasury Department backed the determination of genocide with a raft of sanctions targeting the RSF’s leader, Gen. Mohammed Hamdan Dagalo, as well as seven companies in the United Arab Emirates, the group’s main foreign sponsor, that have traded in weapons and gold on his behalf.

“The RSF and allied militias have systematically murdered men and boys — even infants — on an ethnic basis, and deliberately targeted women and girls from certain ethnic groups for rape and other forms of brutal sexual violence,” Blinken said in a statement. “Those same militias have targeted fleeing civilians, murdering innocent people escaping conflict and prevented remaining civilians from accessing lifesaving supplies.”

The genocide determination comes two decades after the U.S. took a similar step in 2004, when then-Secretary of State Colin Powell determined that the Janjaweed, ruthless ethnic militias allied with Sudan’s military, had committed genocide during a vicious counterinsurgency campaign in Darfur.

The Janjaweed later morphed into the Rapid Support Forces. But instead of being allied with Sudan’s military, the group is now fighting it, in a civil war that has driven one of Africa’s largest countries into a devastating famine, killed tens of thousands of people and forced more than 11 million people — almost one-quarter of Sudan’s population — to flee their homes, according to the United Nations.

Atrocities and war crimes have been committed on both sides, say officials from the U.S., the U.N. and human rights groups. The military has repeatedly massacred civilians in indiscriminate bombing raids, sometimes killing dozens at once.

But only the RSF has been accused of ethnic cleansing, particularly during systematic violence in Darfur between April 2023 — when the civil war began — and November of that year. Its fighters, who are mostly ethnic Arabs, targeted members of the Masalit, a non-Arab ethnic group, in a brutal assault that became a central element of the U.S. genocide determination, said two senior U.S. officials who spoke on condition of anonymity to discuss sensitive diplomatic matters.

The toll of that violence is unclear.

Hundreds of thousands of Masalit have since fled into Chad, where they live in squalid and overcrowded camps — part of an exodus of 3 million Sudanese.