Animal carcasses are rotting and tens of thousands of people have sought shelter in schools and government offices in Sudan's Darfur region after violence this month, the UN said on Thursday.
About 100,000 people are newly estimated to have been displaced or severely affected across a wide area of the Jebel Amir district of North Darfur state, the United Nations humanitarian agency (OCHA) said in its weekly bulletin.
"Many of these people are living in the open in appalling conditions," OCHA said.
It was the worst recent unrest in a region where a decade-long rebellion has been compounded by inter-Arab violence, banditry and tribal fighting.
Amnesty International says Sudanese security officers were reportedly involved in the gold mining-related attacks that killed up to 200 people and led to the massive displacement.
The largest group of 65,000 newly homeless are in El Sireaf, OCHA said, citing figures from the government's Humanitarian Aid Commission.
The El Sireaf district commissioner says schools and public offices have closed "due to the large number of displaced people who have taken refuge in these buildings," OCHA reported.
In the local boys' school alone, 25,000 people have sought refuge while a similar number are in the girls' school, said the commissioner of the district about 250 kilometres (155 miles) northwest of the state capital El Fasher.
"Many displaced people came to the area with their livestock, putting significant pressure on available grazing," OCHA reported.
"This confinement is reportedly causing animal deaths and carcasses are being left unburied posing a serious health risk."
More than one million people were already living in camps for the displaced in Sudan's western region of Darfur, an area roughly the size of France, because of 10 years of conflict.