In a report to the UN Security Council, Luis Moreno-Ocampo on Wednesday said the office had documented "thousands of alleged direct killings of civilians by parties to the conflict", including "a significant number of large-scale massacres, with hundreds of victims in each incident".
Ocampo told the council that his office was investigating allegations that some of the groups implicated in the Darfur crimes "did so with specific genocidal intent".
He said identifying those with the greatest responsibility for the most serious crimes in Darfur was a key challenge for his probe but said he would not draw any conclusions pending the completion of a "full and impartial investigation".
He said the ICC would need the "full support of the Security Council and the unfettered cooperation of the international community, in particular the government of Sudan".
Ocampo said interviews of victims and witnesses reported that men perceived to be from the Fur, Massalit and Zaghawa ethnic groups were "deliberately targeted".
The conflict in Darfur has raged
Evidence cited eyewitness accounts that "the perpetrators made statements reinforcing the targeted nature of the attacks, such as 'we will kill all the blacks' and 'we will drive you out of this land'."
The report also cited a "significant amount of information indicating that thousands of civilians have died since 2003" as a result of lack of shelter and basic necessities for survival after their homes and food stocks were destroyed and their property looted.
Ocampo's office also recorded "hundreds of alleged cases of rape", which the report said was indicative of an endemic practice among some groups involved in the conflict.
It highlighted a "widespread pattern of displacement of civilians, with recent estimates of some two million displaced persons and refugees from Darfur".
"Destruction of property and looting is a prevalent feature of the crimes in Darfur, with reports of destruction and looting in up to 2,000 villages throughout the three Darfur states," it said.
"Destruction of property and looting is a prevalent feature of the crimes in Darfur"
International Criminal Court report
The study covering the October 2002-May 2006 period, also referred to continued reports of direct attacks on humanitarian workers and peacekeepers, including the killing of African Union peacekeepers in 2005 and 2006.
"These attacks are not only grave examples of the potential warcrimes, they also have an impact on the delivery of vital services that exacerbates the suffering of the most vulnerable groups in Darfur," it said.
Meanwhile Omar Manis, Sudan's UN envoy, said his government had set up a special criminal court to deal with the Darfur crimes.
But New York-based Human Rights Watch (HRW) said it was aware of only 13 cases that had been brought before that special court to date.
"The cases have involved low-ranking individuals accused of relatively minor offenses. No senior commanders or superiors have been charged for their part in the atrocities," HRW said.
"The Sudanese government must do more than pay lip service to the idea of justice"
Human Rights Watch
"The cases before the court so far involve ordinary crimes like theft and receiving stolen goods, which don't begin to reflect the massive scale of the destruction in Darfur," Sara Darehshori, senior counsel to the International Justice Programme at HRW, said in a statement.
"The Sudanese government must do more than pay lip service to the idea of justice," she added.
The ICC, based in The Hague, is mandated to try genocide, crimes against humanity and war crimes. It can also try crimes of aggression although member states have not yet agreed on the legal definition for such crimes.
Decades of sporadic conflict in Darfur erupted into all-out war in 2003, when rebels took up arms, accusing the Arab government in Khartoum of neglect and calling for autonomy.
In response, the regime unleashed its Janjaweed proxy militia on Darfur's largely black population. The combined effect of war and famine has resulted in the deaths of up to 300,000 people.