London - Nearly 80 percent of the 300,000 conflict-related deaths in Darfur were due to diseases like diarrhoea, not violence, Belgian scientists said on Friday.

An analysis of deaths dating from 2003, when rebels took up arms against the government of Sudan, showed that after an initial peak of violent deaths in the still-ongoing conflict, diseases associated with diarrhea became the major killers.

The researchers said their results showed that any reduction in humanitarian aid can cause deaths rates to increase sharply, raising "serious concerns" about the consequences of last year's expulsion of aid workers from Sudan by the country's president.

Since the armed rebellion started in early 2003, the United Nations estimates 300,000 people have died and more than 2 million have been driven from their homes after a counter-insurgency campaign by Khartoum.

Diarrhea kills some 1.5 million children each year around the world -- more than AIDS, malaria and measles combined.

The International Criminal Court last year issued an arrest warrant for Sudanese President Omar Hassan al-Bashir for war crimes in Darfur. He rejects the court's authority and puts the death toll at 10,000.