The Emergency Lawyers, who have been documenting human rights abuses during the 20-month war between the army and rival paramilitaries, said the attacks in Um Al-Qura in eastern Al-Jazira began last week as the army advanced through the state.

On Saturday, the military recaptured the state capital, Wad Madani, pushing out the paramilitary Rapid Support Forces, who had dominated Al-Jazira since December 2023.

The lawyers' group on Monday accused the army and allied militias of detaining "a number of civilians, including women", in what they described as a part of campaigns targeting ethnic and regional communities accused of collaborating with the RSF.

They said that the abuses included "extrajudicial killing... kidnapping as well as physical and psychological humiliation and torture".

Both the army and the RSF have been accused of war crimes, including targeting civilians and indiscriminately shelling residential areas.

Though the RSF has become notorious for alleged ethnic-based violence -- leading the United States last week to accuse it of genocide -- reports have also emerged of civilians being targeted on the basis of ethnicity in army-controlled areas.

US special envoy for Sudan Tom Perriello on Tuesday described the attacks as "appalling".

The army "and associated militias must immediately take action to investigate and hold those responsible for such horrors accountable", he wrote on social media site X.

The army on Tuesday attributed the attacks to "individual violations" and pledged to hold perpetrators to account.

It also accused unnamed groups of exploiting the incidents to blame the military while ignoring what it said were "ongoing and horrific war crimes" committed by the RSF.

- Defector implicated -

Villages such as Kambo Tayba -- where the attacks occurred -- are home to communities of Kanabi, residents of informal settlements, traditionally seasonal agriculture workers, who according to the Emergency Lawyers have faced hate speech as well as accusations of aiding the RSF.

Community advocacy group the Kanabi Congress has blamed the "massacre" on the Sudan Shield Forces, a group commanded by Abu Aqla Kaykal that has been a key part of the army's Al-Jazira offensive.

Kaykal in October defected to the army's side, after serving as the RSF's Al-Jazira commander during a time when the paramilitary unleashed a litany of horrors on the agricultural state, including laying siege to entire towns.

The Sudanese doctors' union, a pro-democracy body that has documented abuses on both sides, on Tuesday called the attacks in Um al-Qura "blatant violations of human dignity and rights".

"This includes attacks on civilians under the pretext of their alleged cooperation with the RSF or carrying out retaliatory actions on tribal grounds," they said in a statement.

Since April 2023, Sudan has been devastated by a war that has pitted army chief Abdel Fattah al-Burhan against his former deputy Mohamed Hamdan Daglo, who commands the RSF.

The war has killed tens of thousands, uprooted more than 12 million and pushed the country to the brink of famine in what the United Nations describes as one of the world's worst humanitarian disasters.