KILLINGS, rape, and the razing of houses to the ground are devastating the northern region of South Sudan, as aid agencies withdraw and the UN struggles to secure access.

Eyewitnesses report the targeted rape and killing of civilians, including children. About 100,000 people taking refuge in UN camps at Malakal, Upper Nile State, and Bentiu, Unity State, are now cut off, a spokesman for UNICEF, Jonathan Veitch, said on Tuesday.

"Survivors reported to UNICEF that whole villages were burned to the ground by armed groups while large numbers of girls and women were taken outside to be raped and killed, including children as young as seven," Mr Veitch said. "I don't know why people would do that to children; it's absolutely staggering that it's taking place."

He said that aid workers were unable to leave the camps. More than 650,000 civilians have been left without outside aid.

Since late April, 151 staff members from 22 organisations have been relocated from southern Unity State because of the insecurity.

World Vision announced last week that it was suspending operations in Unity indefinitely. It estimates that more than 10,000 children under the age of five in Unity face malnutrition.

Christian Aid, which supports projects in the state, estimates that up to 100,000 people had to flee their homes in the ten days to 12 May. Its emergency programme officer, Rosie Crowther, warned that the fighting was preventing people from growing crops during the peak of the country's planting season.

"We are working in some of the worst-affected areas to meet immediate food needs, provide safe drinking water, and promote safe hygiene and sanitation practices to help prevent the spread of disease," she said.

The latest UN humanitarian bulletin warns that South Sudan is gripped by a "major public-health crisis". Outbreaks of cholera are expected, alongside acute respiratory infections, malaria, malnutrition, and measles.

Two million people have been displaced by the conflict, which broke out in December 2013 when President Salva Kiir accused Riek Machar, his former deputy, of attempting to stage a coup ( News, 20 December 2013).

Government and opposition forces have both been held responsible by the UN Security Council for violating the Cessation of Hostilies Agreement signed in January last year. Sanctions are threatened.

Anglican agencies are supporting the humanitarian effort through the Sudanese Development and Relief Agency, an arm of the Episcopal Church of South Sudan & Sudan. Its general manager, the Revd Joseph El-hag Abe Natana, told the Episcopal News Service last week that aid, political lobbying, and prayers were seen "as God's care, support, and intervention".