Up to 10,000 displaced Sudanese people, many of them children, are dying each month in Darfur region as a result of disease and violence, a UN agency says.
More than a million people have fled their homes in Darfur
Despite major aid efforts, death rates continue to exceed the threshold for a humanitarian emergency, a study by the World Health Organization said.
Its director-general said emergency aid needed to be increased urgently.
The EU meanwhile urged the United Nation to investigate claims that genocide is taking place in Darfur.
At a meeting in Brussels, European Union foreign ministers also warned Sudan of possible sanctions unless it took action to disarm militias threatening refugees in Darfur, western Sudan.
Last week, Sudan categorically rejected a statement by US Secretary of State Colin Powell in which he described the killings in Darfur as genocide.
The WHO said the interview-based survey in West and North Darfur - carried out together with the Sudanese government - pointed to a monthly toll of 6,000-10,000 people among the internally displaced population of about 1.2 million.
More than 1m displaced
Up to 50,000 killed
More at risk from disease and starvation
Arab militias accused of ethnic cleansing
Sudan blames rebels for starting conflict
The "crude mortality rate" used to define a humanitarian crisis is one death per 10,000 people per day. In West Darfur the mortality rate was 2.9, while in North Darfur it was 1.5.
The survey's results between June and August showed that displaced people in North and West Darfur were dying at between three and six times the expected rate, the WHO said.
"Thousands, including thousands of children under five are dying every month from diseases which can be easily prevented and treated," the WHO Director-General, Lee Jong-Wook said, urging an increase in emergency aid.
Diarrhoea was the leading cause of deaths, particularly amongst children, WHO's crisis action group head Dr David Nabarro said.
He added that it was it was particularly disturbing to see such high death rate six months after UN and other aid agencies began sending aid to Darfur refugees.
The survey also showed said many people did not have enough clean water and lived in crowded makeshift settlements.
Injuries and violence were linked to 15% of deaths, but the survey did not go into detail of the nature of the violence.
The WHO said the results were in line with an estimate of 50,000 dead in Darfur since the conflict broke out last year.
An estimated one million people have been made homeless during the conflict in Darfur between government forces and rebel groups, which broke out last year.
The US says the government in Khartoum is failing to prevent atrocities against civilians by the pro-government Janjaweed Arab militia.
The US is seeking a new UN resolution that threatens Sudan with sanctions.
The proposed resolution says Sudan has failed to fully comply with a previous UN resolution which was passed in July. It gives the government a new 30-day deadline.
The US would like the Security Council to vote on its new draft resolution next week.