The report was commissioned by the human rights council in an emergency session last December.
After attempting to enter Sudan for around three weeks in February, the council concluded that the Sudanese government had no intention of co-operating with the United Nations.
"Clearly, Darfur needs help from the rest of the world"
Jack, Houston, USA
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The team was led by Jody Williams, a Nobel peace prize laureate, who told Al Jazeera that the international community needed to intervene more strongly in Darfur and that "words without action are irrelevant."
"People do not deserve to die because of the actions of a few men in Khartoum," she said.
The report urged stronger UN Security Council intervention, sanctions and criminal prosecution.
The violence in Darfur has claimed tens of thousands of lives and forced around 2.5 million people from their homes as rebels fight pro-government militias.
Some, including the US government, have described the violence as genocide.
"The principal pattern is one of a violent counterinsurgency campaign waged by the government of the Sudan in concert with janjaweed militia, and targeting mostly civilians," the report says.
"Rebel forces are also guilty of serious abuses of human rights and violations of humanitarian law."
The report said important steps have been taken by the international community, including the African Union and the UN, but "these have been largely resisted and obstructed, and have proven inadequate and ineffective."
Humanitarian agencies say they face mounting difficulties in getting help to the desperately needy, and increasingly aid workers themselves are targets of the violence.
|Around 2.5 million people have been|
displaced by the conflict [EPA]
The government in Khartoum rejects the use of the term genocide and says the numbers pertaining to the conflict are exaggerated.
It blames rebel groups which refused to sign up to a peace deal in 2006 for the worst of the abuses and accuses the Western of blowing the conflict out of proportion.
However, last month Sudan's government was linked directly to the atrocities in Darfur, by prosecutors at the International Criminal Court in the Hague who named a junior minister as a war crimes suspect who helped recruit, arm and bankroll janjaweed fighters.
Ahmed Muhammed Harun, the former junior interior minister responsible for the western region of Darfur, and a janjaweed militia leader, Ali Mohammed Ali Abd-al-Rahman, also known as Ali Kushayb, are suspected of a total of 51 counts of war crimes and crimes against humanity, according to Luis Moreno-Ocampo, a prosecutor.
Although the UN team was unable to enter Sudan, it held consultations with a number of aid agencies working in the region and was briefed by officials of the African Union in Addis Ababa.
In Ndjamena, Chad, the team spoke to members of rebel groups, including the Justice and Equality Movement and the secretariat of the National Redemption Front.
In order to get witness reports of the suffering of the civilian population the team spoke refugees from Darfur in eastern Chad.
Williams denied the report lacked credibility because of the team's inability to enter Darfur.
She told Al Jazeera that Khartoum was keen to promote the idea the report lacked credibility as it opposed the investigation from the start and that such a response was "very predictable."
The decision to send the six-person team to Sudan was taken by the human rights council after a bitter debate last December when some Arab and African member countries on the 47-state body had resisted singling out Sudan for special attention.
The council is due to debate the mission's report on Friday.