About 500 children have died of starvation since the start of the war in Sudan

About 500 children have starved to death in Sudan - including dozens of babies at a government-run orphanage in the capital Khartoum - since war broke out in the country in April, Save the Children said on Tuesday.

The organization also said at least 31,000 children lack access to treatment for malnutrition and related illnesses after the charity was forced to close 57 of its feeding centers in Sudan.

War in Sudan erupted on April 15 after months of tensions between the army and rival paramilitary forces. The conflict has turned Khartoum and other urban areas into battlefields. Many residents live without water and electricity, and the country's health care system has nearly collapsed.

"We never thought we would see children dying of hunger in such numbers, but this is now the reality in Sudan," said Arif Noor, director of Save the Children's Sudan headquarters. "We are seeing children dying of completely preventable hunger."

Violence in Sudan is estimated to have killed at least 4,000 people, according to Liz Throssell, a spokeswoman for the UN human rights office. Activists and doctors on the ground, however, say the death toll is likely to be much higher.

More than 4.4 million people were forced to flee their homes, go to safer areas in Sudan or move to neighboring countries, according to the UN migration agency.

Save the Children said that between May and July, at least 316 children, mostly under 5, died of malnutrition or related diseases in the southern province of White Nile. More than 2,400 more children have been admitted to hospitals in the past eight months with severe acute malnutrition - the deadliest form of malnutrition.

In eastern Qadarif province, at least 132 children died of malnutrition at the government-run Children's Hospital between April and July.

And at least 50 children, including dozens of infants, died of starvation or related illnesses at an orphanage in Khartoum in the first six weeks of the conflict after fighting prevented Save the Children staff from entering the building to care for them, said this organization.

Save the Children also warned that special food supplies to treat malnutrition were running critically low in 108 facilities still operating across Sudan.

Meanwhile, fighting has flared this week around a military camp south of Khartoum as the paramilitary Rapid Support Force has tried to take over the strategically important facility, the warring parties reported.

Heavy fighting was reported last week in Nyala, the provincial capital of South Darfur. The Darfur region had some of the worst periods of violence as fighting turned into ethnic clashes.