In a statement released, she highlighted the devastating impact of the conflict on children, with at least 43 people, including children and women, killed in recent weeks.
"There are deeply concerning reports of children being separated from their families or reportedly going missing," she said, emphasizing the urgent need for parties to the conflict to step back from the brink of a potentially catastrophic confrontation, especially with the looming threat of an imminent military attack on El Fasher.
Russel underscored the dire situation facing the city, which shelters at least 500,000 people displaced by violence, with the lives and wellbeing of 750,000 children at risk.
"At the same time, a severe lack of humanitarian access and an inability to deliver commercial goods due to the insecurity have led to the scarcity of essential services and rocketing costs for water, food, and fuel. More than 330,000 people are reportedly facing acute food insecurity in El Fasher," she added.
Urging all parties to the conflict to prioritize the protection of civilians, and allow the safe movement of those seeking refuge in safer areas, she also called for rapid and unimpeded humanitarian access.
She said that the escalating violence in Sudan is pushing the country towards a conflict-induced famine and urged immediate action to prevent further loss of life, especially among children.
The Sudanese army controls El Fasher, and it is supported by armed movements that signed the Juba peace agreement with the government in 2020.
The war in Sudan broke out in April 2023 over disagreements about integrating the RSF into the army between army Gen. Abdel Fattah al-Burhan and RSF commander Mohamed Hamdan Dagalo.
The conflict has caused a devastating humanitarian crisis, and clashes have killed nearly 16,000 people and displaced millions.
On March 29, Sudan filed a complaint with the UN Security Council against the United Arab Emirates for allegedly supporting the RSF, which the UAE denied.