Warnings of worsening humanitarian conditions in Sudan continue, despite reports of a ceasefire deal brokered by international mediators on Thursday.
"Today, traumatised civilians are still trapped inside El Fasher and are being prevented from leaving," said UN human rights chief Volker Türk in a statement released on Friday.
"I fear that the abominable atrocities such as summary executions, rape and ethnically motivated violence are continuing within the city."
The statement comes amid mounting reports from UN human rights watchdogs and other experts of widespread violence and war crimes after the city of El Fasher fell to the Rapid Support Forces (RSF) militia on 23 October this year, which has been battling former allies-turned-rivals - the military government in Khartoum - for control of Sudan for over two years.
Violence continues even for those who managed to flee the city, since exit routes have become scenes of "unimaginable cruelty," Mr. Türk added.
No sign of de-escalation
The High Commissioner said that since the capture of El Fasher civilian casualties, destruction and mass displacement have been mounting.
He further warned that developments on the ground show "clear preparations for intensified hostilities, with everything that implies for its long-suffering people."
In an interview with UN News on Thursday, UN Special Adviser on genocide prevention Chaloka Beyani raised concerns over allegations of war crimes in El Fasher.
"We see massive violations of international human rights law, direct attacks on civilians, non-compliance with international humanitarian law, which regulates conduct in relation to hostilities, and that the attacks are largely on civilians," he said.
On Friday, UN independent experts also voiced concern over the humanitarian situation, pointing out "sadistic levels" of sexual violence and abuse.
"We are appalled by credible reports of ethnically targeted summary executions of civilians in El Fasher by the RSF, which are prohibited under international law and constitute war crimes and may also amount to crimes against humanity," they said. "They must cease immediately and prompt independent investigations are critical."
Reported ceasefire agreement
The RSF reportedly agreed to a ceasefire on Thursday, proposed by the United States and Arab countries - but the national army has not signed on and attacks are continuing, according to news reports, including explosions around government-held Khartoum.
Meanwhile, UN agencies continue to push for an end to hostilities.
"The Security Council 's arms embargo is clear: the provision of continuing military support to sustain parties committing serious violations must stop," said Mr. Türk.
He repeated his plea for an "immediate end to the violence both in Darfur and Kordofan," adding that "bold and urgent action is required by the international community."
The UN Human Rights Council will hold a special session on the situation in and around El Fasher, on Friday 14 November.
