The United Nations' World Health Organization issued new figures saying 6,000 to 10,000 people are dying per month there in one of Africa's worst humanitarian crises.
Rebels from the Justice and Equality Movement group said talks failed due to continuing disagreements with the Khartoum government over security issues, but they hoped to resume negotiations in a month, Reuters reported.
Darfur's other rebel group, the Sudan Liberation Movement, said it was still uncertain whether to continue talks and may decide later Wednesday.
Members of the Sudanese government denied that talks had collapsed, saying African Union mediators were meeting with all parties later in the day. African Union representatives were not available for comment, according to Reuters.
Rebels have insisted that the Sudanese government agree to certain security demands such as disarmament of the pro-government Arab Janjaweed militia and a no-fly zone over Darfur.
The government, which denies it supports the Janjaweed, has demanded that rebels start moving their troops to containment areas.
More than 1 million people have fled their homes in the western province of Darfur from attacks by the Janjaweed. The United Nations estimated that at least 50,000 people have died from violence, starvation or illness in the conflict, and up to 10,000 more are dying each month.
The main killers are preventable conditions such as diarrhea, which account for nearly a quarter of the deaths, and violence that has plagued the region since civil war began in February 2003, reports the Washington Post.
Sudan challenged the findings of the survey, saying mortality rates among the displaced people are actually improving. "I do not think this assessment is correct. The death rate is decreasing," said Sudan's Minister of Humanitarian Affairs Ibrahim Mahmoud Hamid, according to the Post.
The Bush administration recently called the ongoing killing of black Africans in the Darfur region "genocide." The United States is pushing the U.N. Security Council to adopt a resolution this week threatening oil industry sanctions against Khartoum if it does not crack down on the militia and allow thousands of additional African monitors into Darfur.
Sudan on Wednesday rejected the resolution, calling it "imbalanced" and "unfair."
The European Parliament is also set later this week to call the violence in the region "tantamount to genocide," according to a draft resolution heading to a vote Thursday, Reuters reported.