"We lost 28 of our men and we killed 100 from the other side," Ahmed Khiri, a Misseriya tribal leader, told AFP.
He was referring to fighting with the Salamat group outside of Garsila town in western Darfur yesterday.
Khiri said 17 more fighters on the Misseriya side were wounded and there was a threat of further violence.
"Troops from both sides are gathering in different areas," he said.
A Salamat leader said: "A huge number of people were killed on both sides.
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Scores more have been killed, according to both sides, since the latest outbreak of warfare between the Misseriya and Salamat began last week.
"The government promised to send troops from Zalingei to intervene between the two parties but they are not here yet," the Salamat leader said, referring to the capital of Central Darfur state.
Sudan's army spokesman could not be reached.
Garsila is about 150 kilometres (90 miles) north of the Abugaradil area, where last week's battles between Misseriya and Salamat killed 94 people, mostly Salamat, Khiri said at the weekend.
Inter-tribal and inter-ethnic fighting has been the major source of violence in Darfur this year, where an estimated 300,000 people were displaced in the first five months alone, the African Union-UN peacekeeping mission in Darfur (UNAMID) says.
That is more than in the previous two years combined.
The United Nations says that, as of the end of June, 30,000 Sudanese had fled into Chad because of the tribal fighting in southwestern Darfur as well as similar unrest in North Darfur.
The two tribes signed a peace agreement on July 3 under which they were to pay compensation to each other, and refugees would return.