A convoy carrying blankets, water and other supplies began a days-long journey on Sunday to deliver emergency assistance in Sudan's Darfur where about 100,000 people have been affected by recent violence, the UN said.
"We have sent out a further 100 metric tonnes of assistance," Damian Rance, of the United Nations humanitarian agency (OCHA), told AFP. "It started rolling this morning, I believe."
Amnesty International says Sudanese security officers were reportedly involved in the gold mining-related attacks earlier this month that killed up to 200 people and led to the massive displacement across a wide area of North Darfur state's Jebel Amir district.
Rance said the number displaced or severely affected in this one incident is close to the figure for those displaced throughout Darfur all last year.
"I think the sheer scale of it is significant," he said.
Aid trucks will need four or five days, travelling over rough terrain, to cross more than 250 kilometres (155 miles) from the state capital El Fasher to El Sireaf where children are sleeping outside in the desert, Rance said.
"In an open desert area, it does get quite cold," he said.
The aid also includes health and nutrition supplies, animal feed and vaccines.
OCHA, citing figures from the government's Humanitarian Aid Commission, said the largest group of 65,000 newly homeless are in El Sireaf, where many have crowded into schools and other public buildings.
People fled with their livestock, which has put significant pressure on available grazing and led to the deaths of animals, OCHA reported.
The 100 tonnes of new aid will complement more than 600 tonnes of relief, including food for more than 60,000 people, which the UN and its partners had already delivered.
Fighting began on January 5 between members of the Beni Hussein tribe and another Arab group, the Rezeigat, when a Rezeigat leader who is an officer in Sudan's Border Guard force apparently laid claim to a gold-rich area in Beni Hussein territory, Amnesty said.
The two tribes have reached an agreement to end the conflict, state-linked media reported on Saturday.
More than one million people were already living in camps for the displaced in Darfur, an area roughly the size of France.
A decade-long rebellion has been compounded by inter-Arab violence, banditry and tribal fighting.
Sudan's President Omar al-Bashir is wanted by the International Criminal Court for war crimes, genocide and crimes against humanity allegedly committed in Darfur.