A paramilitary group at the centre of the four-month conflict in Sudan has been singled out by leading rights group and 30 United Nations experts, accused of carrying out rape and sexual violence against women in separate statements, according to Al Jazeera.

Sudan plunged into chaos on April 15 after simmering tensions between the paramilitary group, the Rapid Support Forces (RSF), and the Sudanese Armed Forces exploded into open fighting.

New York-based Human Rights Watch said on Thursday that the RSF group apparently targeted non-Arab women and girls in the western Darfur region, as well as activists documenting human rights abuses during the conflict.

“The Rapid Support Forces and allied militias appear responsible for a staggering number of rapes and other war crimes during their attack on El Geneina,” HRW’s crisis and conflict director, Belkis Wille, said in a statement.

“The UN Security Council should show those responsible for abuses that the world is watching by taking urgent steps to bring an end to these atrocities.”

HRW said it documented 78 victims of rape between April 24 and June 26.

UN officials warned in June that the fighting in Darfur has taken an ethnic dimension, with the RSF and allied militias targeting African communities.

Darfur was the scene of genocidal war in the early 2000s, when state-backed Arab armed groups known as the Janjaweed were accused of widespread killings, rapes and other atrocities. The Janjaweed later evolved into the RSF.

Several victims, who had fled Darfur for neighbouring Chad, told HRW they were targeted because they were from the African Masalit community or because they were activists reporting on the conflict. At least one victim said she was pregnant after being raped by a paramilitary member.

In the report, the rights group stated it spoke with nine women and one girl who said they had all been victims of rape, four by multiple men.

HRW also spoke with four women who witnessed sexual assaults as well as five service providers, including medical workers, who provided victims with support in El Geneina, the West Darfur capital.

Also on Thursday, a group of 30 independent UN experts expressed alarm at reports “of widespread use of rape and other forms of sexual violence” by the RSF.

“Hundreds of women have been detained by the RSF, held in inhuman or degrading conditions, subjected to sexual assault, and are vulnerable to sexual slavery,” UN experts said in the report.

The group called on the RSF to “demonstrate its commitment to upholding humanitarian and human rights obligations”.

The International Criminal Court’s prosecutor, Karim Khan, told the UN Security Council last week that the body was investigating alleged new war crimes and crimes against humanity in Darfur.

At least 4,000 people are estimated to have been killed in the conflict, the UN human rights office said. Activists and doctors on the ground say the death toll is likely far higher.

According to the latest UN statistics, the conflict has displaced more than 4.3 million people. More than one million people have fled to neighbouring countries, such as Egypt, Chad, Ethiopia, the Central African Republic, and South Sudan.