UNITED NATIONS — How many people have died in Darfur? Two years ago, the United Nations estimated 200,000. But the man who gave that figure now says it's far too low. Sudan has long said it's way too high.

A new mortality survey might settle the question, but the U.N. has no plans for one — it is too busy trying to help the living. Activist groups say Sudan's government doesn't want one.

Former U.N. humanitarian chief Jan Egeland told The Associated Press he has no doubt that tens of thousands more people have died since he made the 200,000 estimate in 2006. He cited a dramatic increase in the number of people affected by the conflict and a surge in fighting.

But Egeland, now a special adviser to Secretary-General Ban Ki-moon, said only a large-scale mortality survey and access to areas where aid workers are unable to reach could provide an accurate death figure for the five-year-old conflict.

Aid workers long have been prevented from reaching parts of Darfur because of Sudanese government obstruction and the unrelenting violence between ethnic African rebels and the janjaweed militias that support the Arab-dominated regime in Khartoum.

Sudan's government strongly disputes the figure of 200,000 deaths, contending the toll is a tiny fraction of that — less than 10,000.

Aid workers say Sudan's figure probably reflects people killed by bullets, but doesn't take into account all those who have died from hunger or disease tied to the upheaval of the conflict.

The last official, independent mortality survey for Darfur was released in March 2005 based on data collected from 8,844 displaced people living in camps by a team from the World Health Organization. It estimated 10,000 people had died among the refugees each month between the end of 2003 and October 2004 — mostly of malnutrition and disease.

Egeland said when he was interviewed at the end of 2005, "I just added the 10,000 we found that died per month in 2004. ... I said well it's 18 months, it's 180,000." A few months later he raised it to 200,000.

"Then, the clock stopped ticking, sort of," he said in the AP interview earlier this month.

"You have the figure 200,000 people died in Darfur which has been used continuously since I gave it," Egeland added. "Please stop using that figure. I gave it. It's two and half years old. It's wrong."

Christina Bennett, a spokeswoman for Egeland's successor, Undersecretary-General for Humanitarian Affairs John Holmes, said the U.N. Office for the Coordination of Humanitarian Affairs has no plans for a new mortality survey.

"We're working as hard as we can to assist the living," she said. "It is likely that more than 200,000 people have died, but what we focus on is not the number of people who have died but the 4 million people who are needlessly suffering in Darfur."

Bennett said that to calculate the number of deaths in Darfur "would require a complex and thorough survey, which we feel under current circumstances would be extremely time consuming and expensive, and any real accuracy in those numbers would be impossible to achieve."

John Prendergast, co-chairman of the Washington-based Enough Project, which works to end genocide and crimes against humanity, countered that mortality studies can be done with a few epidemiologists and aren't that costly or time consuming.

"The problem is twofold: The government of Sudan does not want a new mortality study done for Darfur, and because of that the United Nations won't pursue it," he said Thursday.

Eric Reeves, a Sudan researcher and analyst at Smith College, agreed that the Sudanese government has no interest in a new mortality study.

"If we refuse to acknowledge that deaths are well in excess of 200,000 — a figure that has grown very stale over the past one and a half years — we risk failing to understand how great the impending human destruction may be in Darfur and in eastern Chad," he told the AP.

The 4 million people in desperate need of aid represent nearly two-thirds of Darfur's estimated population of 6.5 million. Some 2.5 million of those in dire need live in refugee camps in Darfur and neighboring Chad, while the others are in remote villages, the U.N. says.

One of the major problems in calculating deaths is that Darfur is a sprawling, harsh and arid region nearly the size of Texas, and large numbers of people flee their homes every month to escape violence or seek food.

Some in the U.N. say the mortality rate from the conflict has improved since Egeland's initial calculation.

Bennett, the spokeswoman, said humanitarian workers had arrived in Darfur in large numbers and been able to save many lives. "For example, there have been no epidemics, and severe malnutrition is below emergency levels," she said.

Richard Garfield, who coordinates the health and nutrition tracking service at the WHO in Geneva, said Tuesday that seven mortality surveys in 2007 among the internally displaced or residents of Darfur showed "expected levels of mortality." Each survey covered about 1,000 households, and not more than 2,000 households.

"Darfur is not experiencing the very high levels of mortality it was experiencing up to a few years ago. So the job now is to assist those who can be assisted and to provide security so others can be reached," Garfield said.

But he conceded the studies involved only areas where aid groups have been able to work. "We don't know the situation in areas that can't be reached," he said.

Some researchers and human rights advocates contend violence has persisted at the same level, or even worsened, since March 2005, meaning total deaths now could be as high as 400,000.

Egeland believes 400,000 "is a much more correct figure than 200,000."

He noted the 2005 estimate of 10,000 deaths a month came when the war was seriously affecting some 1 million people.

"The mortality has gone down because of successful relief to the refugees, but there are now 4 million people affected, not 1 million," Egeland said. "So many more people are affected, and, of course, the excess number of deaths must be still 10,000 of these 4 million people."

Prendergast, at the Enough Project, agreed that "the number would be much closer to 400,000 than 200,000."

Reeves, the Smith College researcher, believes the number of dead could be closer to 500,000 in Darfur and eastern Chad.

Allyn Brooks-LaSure, spokesman for the Save Darfur Coalition, said "there are no concrete numbers" because "when epidemiologists try to get in, the Sudanese don't let them in."

"What we say is the number could be as many as 400,000 due to violence, disease and starvation. But no one knows for sure," Brooks-LaSure said.