The EU said on Sunday it was "appalled" by reports of more than 1,000 people killed this month in Sudan's West Darfur in an apparent "ethnic cleansing campaign"by the paramilitary Rapid Support Forces (RSF).

"These latest atrocities are seemingly part of a wider ethnic cleansing campaign conducted by the RSF with the aim to eradicate the non-Arab Masalit community from West Darfur, and comes on top of the first wave of large violence in June," EU foreign policy chief Josep Borrell said in a statement.

Since April, forces loyal to army chief Abdel Fattah al-Burhan – Sudan's de facto head of state – have been at war with the RSF commanded by his former deputy, Mohamed Hamdan Daglo.

The European Union statement said there were "credible eyewitness reports (that) more than a thousand members of the Masalit community were killed in Ardamta, West Darfur, in just over two days, during major attacks carried out by the Rapid Support Forces (RSF) and its affiliated militias."

The toll was higher than a previous one of 800 given by the UN refugee agency (UNHCR), which said 100 shelters in a displaced persons' camp in Ardamta had been razed.

"What is happening is verging on pure evil," the UN humanitarian coordinator for Sudan, Clementine Nkweta-Salami, said on Friday, citing reports of young girls being raped in front of their mothers.

She voiced fears of a repeat of the genocide campaign that gripped Darfur in the early 2000s.

The EU stressed that Sudan's warring sides "have a duty to protect citizens." It said it was working with the International Criminal Court to document violations "to ensure accountability."

"The international community cannot turn a blind eye on what is happening in Darfur and allow another genocide to happen in this region," it said.

More than 10,000 people have been killed in the Sudan conflict so far, according to a conservative estimate by the Armed Conflict Location & Event Data project.

The war has displaced more than 4.8 million people within Sudan and has forced a further 1.2 million to flee into neighbouring countries, according to UN figures. (AFP)