Flagrant rights violations by Sudan's warring parties require the deployment of an "independent and impartial force" to protect millions of civilians driven from their homes, UN experts said Friday.
An independent fact-finding mission said it had uncovered "harrowing" violations by both sides, "which may amount to war crimes and crimes against humanity".
The conflict erupted in April last year pitting the national army led by General Abdel Fattah al-Burhan against the paramilitary Rapid Support Forces of his former deputy, Mohamed Hamdan Daglo.
It has triggered one of the world's worst humanitarian crises.
Tens of thousands of people have been killed, and the experts said eight million civilians have been displaced while a further two million people have fled to neighbouring countries.
More than 25 million people -- more than half its population -- meanwhile face acute hunger, with full-blown famine declared in a camp for displaced people in Sudan's volatile Darfur region.
Mohamed Chande Othman, chair of the fact-finding mission called for "urgent and immediate action to protect civilians".
"It is imperative that an independent and impartial force with a mandate to safeguard civilians be deployed without delay," Othman said.
He said there were different options including a UN mandated one or a regional force backed by the African Union.
- 'Complicit' -
The team reiterated calls for a ceasefire and recommended expanding an existing arms embargo in Darfur to all of Sudan, warning that countries supplying weapons and ammunition to the warring parties could be considered "complicit".
They "run the risk of being held accountable for violations of human rights and international humanitarian law," mission member Joy Ngozi Ezeilo told reporters.
The independent experts, who do not speak on behalf of the UN, said they found evidence of "indiscriminate" air strikes and shelling against civilian targets including schools, hospitals and water and electricity supplies.
"The warring parties also targeted civilians... through rape and other forms of sexual violence, arbitrary arrest and detention, as well as torture and ill-treatment," the mission said.
"These violations may amount to war crimes."
The team found evidence that the RSF and allied militias had committed additional war crimes including sexual slavery, pillaging and recruiting child soldiers.
It said there were grounds to believe that some of these amounted to crimes against humanity.
"Criminal responsibility for all violations is key," mission member Mona Rishmawi told reporters.
- 'Wake-up call' -
The team called on Sudanese authorities to cooperate fully with the International Criminal Court (ICC), and to surrender all those already indicted, including former President Omar Al Bashir.
But given Khartoum's lack of cooperation, the report called for the establishment of a separate international judicial mechanism working in tandem with the ICC.
"Our findings should serve as a wake-up call to the international community to take decisive action," Rishmawi said.
The fact finding mission was created last year by the UN Human Rights Council.
Sudan's government has declined to comment officially on the mission's findings, which were based on interviews with dozens of survivors, witnesses and other sources now in Chad, Kenya and Uganda.
The rights council will next month decide consider extending the mission's initial one-year mandate.
Ezeilo stressed the need for far more focus on the tragedy unfolding in Sudan.
"It is really heartbreaking and definitely the world needs to do much more," she said. "This must be on the front burner of international discussions."