At least 180,000 people may have died in Sudan's Darfur region over the past 18 months, according to the United Nations' top emergency relief official.
Many refugees have died from preventable causes
Jan Egeland said the figure refers to victims of illness and malnutrition and excludes those who have been killed in the ethnic violence.
The UN previously gave an estimate of 70,000 non-conflict deaths.
Pro-government militia are accused of killing and raping villagers and driving two million from their homes.
The UN has not put a figure on violent deaths in the region.
An average of 10,000 people have died each month over the past year-and-a-half from disease and other preventable causes, the emergency relief chief said.
"It could be just as well more than 200,000 [over 18 months] but I think 10,000 a month... is a reasonable figure," Mr Egeland told AFP news agency.
Last year, the World Health Organisation said it believed 10,0000 people had died each month from March to October, mostly from disease and some from random violence in camps.
Amnesty International's best estimate for how many may have died from violence since the conflict began - taking into account attacks on hundreds of villages - was 50,000 as of last month.
Most of the estimated two million people who fled their villages since the violence began in early 2003 have sought refuge in the camps in Darfur's main towns.
As many as 200,000 have also sought safety in neighbouring Chad.
A UN report earlier this year concluded that while the killings in Darfur did not amount to genocide, killings, torture, enforced disappearances and sexual violence were carried out on a widespread and systematic basis and could amount to crimes against humanity.
The BBC's Susannah Price at the UN says the latest reports from Darfur say lawlessness and attacks by the Janjaweed militia continue to blight the lives of civilians.
The Janjaweed attacked villages, targeted an internally displaced peoples camp and burnt abandoned homes to discourage those who wanted to return, she says.