"Over 16,600 cases of acute watery diarrhoea in the past 10 months alone were reported with 317 deaths, which is a rate double than the alert level."

This is according to Unicef. The UN agency has warned that the outbreak could worsen ahead of the rainy season, raising a previous death toll of 279 reported by UN agencies in late May.

The UN children's agency said cases of suspected acute diarrhoea were reported across 12 of the North African country's 18 states during this period.

The central state of White Nile was the most affected, Unicef said in a statement, with more than 5,800 reported cases.

"In the White Nile state, with almost 100,000 refugees living mostly in camps, the situation could worsen as the rainy season begins," the statement quoted Unicef Sudan representative Abdullah Fadil as saying.

"This is deeply worrying."

The other most affected states were East Darfur, North Darfur, South Darfur, South Kordofan and West Kordofan, said Unicef.

"Children continue to be the hardest hit," Fadil said, adding that immediate help was needed to support them.