The "crucial element of genocidal intent appears to be missing", said the report, released on Monday. It recommended that the rights abuses be dealt with by the International Criminal Court based in The Hague.
The report, compiled by a five-member commission set up by UN Secretary-General Kofi Annan in October, said the absence of a genocidal policy "should not be taken in any way as detracting from the gravity of the crimes perpetrated".
It blamed government forces and militias for indiscriminate attacks, including the killing of civilians, torture, enforced disappearances, destruction of villages, rape, pillaging and forced displacement throughout Darfur.
However, it stipulated that such acts did not carry the specific intent to annihilate a group distinguished on racial, ethnic, national or religious grounds, and thus stopped short of genocide.
"Rather it would seem that those who planned and organised attacks on villages pursued the intent to drive the victims from their homes, primarily for purposes of counter-insurgency warfare," it said.
About 70,000 people are estimated to have died in Darfur, many from hunger and disease, in the past several months, while about 1.5 million others have been displaced, many into squalid and dangerous camps.
Also on Monday, Sudan said it would grant the demands of a poor eastern tribe for more wealth and power, two days after security forces killed 18 people at a march in the eastern city of Port Sudan.
Red Sea state governor Hatim al-Wasiyla said the government would meet the Beja tribe's demands, including the appointment of a governor from the region, after April when a peace deal to end more than two decades of civil war in Sudan's south comes into force.
The deal gives wider federal powers to Sudan's 26 states.
"All these demands are in the peace deal and will be implemented after April," al-Wasiyla said. "They know that so there was no need for them to turn to violence."
Port Sudan's police chief Khalaf Allah Muhammadain said there was widespread looting and riots in Port Sudan on Friday night and the police had information the marchers would cause trouble on Saturday.
"It was clear that they had light weapons - knives and other things. They attacked the forces so they were forced to retaliate and opened fire"
Khalaf Allah Muhammadain,
Port Sudan police chief
"It was clear that they had light weapons - knives and other things," he said. "They attacked the forces so they were forced to retaliate and opened fire."
Surviving demonstrators said they were unarmed and were not behind the looting, robbing or burning of shops on Friday. The store owners did not know who was behind the destruction either.
Al-Wasiyla said a committee would be formed to see whether excessive force had been used against the demonstrators on Saturday.
He denied witness reports that security forces had gone on the rampage in ethnic Beja parts of Port Sudan, breaking into homes after the march ended. Many of the wounded said they were in their homes when they were shot.
A Reuters witness saw dozens of bullet holes, spent cartridges and bloodstained beds where people had been shot in several homes in the Beja area of the city, near where demonstrators had gathered for the march.
Beja residents of Port Sudan said security forces had carried out arrests, opened fire and broken into homes at a distance of up to 4km from the site of the march on Saturday.
"They were shouting: 'Beja where are you, come out come out - you are animals'," said Tuhada Ibrahim. "We did not come out and they broke into our houses and shot everything," she said, holding five empty bullet shells she took from her home.