They blame both sides for war crimes including murder, mutilation and torture and warning that foreign governments that arm and finance them could be complicit.
The fact-finding team, in its first report since being created by the UN's main human rights body in October 2023, also accused the paramilitary Rapid Support Forces, which are fighting Sudan's army, and its allies of crimes against humanity including rape, sexual slavery and persecution on ethnic or gender grounds.
The experts called for an expansion of an arms embargo on Sudan's long-restive western Darfur region to the entire country.
The findings from the team mandated by the 47-country Human Rights Council come as more than 10 million people have been driven from their homes - including more than two million to neighbouring countries - and famine has broken out in one large camp for displaced people in Darfur.
The conflict that erupted in April 2023 has killed untold thousands of people, and humanitarian groups are struggling to gain access to people in need.
In December, the UN Security Council voted to end the world body's political mission in the country under pressure from the military leadership.
While the killings, displacements and forced starvation have been long known, the call for creation of an independent force marks the latest sign of desperation from rights advocates both within the country and abroad to halt the bloodshed, displacement and food crisis.
"Given the failure of the parties to protect civilians so far, the fact-finding mission recommends the deployment of an independent and impartial force with a mandate to protect civilians in Sudan," the team's report says.
The experts did not specify what might make up that force, nor did they say which countries might be complicit in the crimes through their backing of rival sides.
Sudan's military has accused the United Arab Emirates of supporting the RSF, a claim the Gulf country has denied.
Neighbouring Egypt is among the backers of Sudan's armed forces.
"The fact-finding mission considers that fighting will stop once the arms flow stops," the report says.
It called for an immediate end to funnelling weapons, ammunition and other support to any side, "as there is a risk that those supplying arms may be complicit in grave violations of human rights and humanitarian law".
The experts focused on a period from January and August.
They visited three neighbouring countries and took testimonies from more than 180 survivors, relatives and witnesses to the conflict that now has spread to 14 of Sudan's 18 states.
Talks in Geneva in September convened by the United States, Switzerland and Saudi Arabia made some headway in getting aid into Sudan, but mediators lamented the lack of participation of Sudan's armed forces. Egypt, the UAE, the African Union and the United Nations were also involved in the talks.
14°C