Save the Children suspended its operations in south Darfur on Monday after two of its aid workers were killed during a roadside ambush.
Abhakar el Tayeb, a medical assistant, and Yacoub Abdelnabi Ahmed, a mechanic, were shot while travelling in a convoy of three vehicles.
The two, who were recruited in Sudan, were part of a mobile health clinic.
The suspension will disrupt medical care and food distribution less than a week after the UN said that the aid agencies were struggling to contain the humanitarian crisis.
Save the Children called its 30 staff in south Darfur back to its regional headquarters at Nyala to review the situation. The organisation hopes the suspension will be temporary, but security in the area has been getting worse.
Its spokesman Laura Conrad said the impact would be far-reaching. ”If there are places we can’t go for security reasons, it will be the same for other aid agencies.”
The charity said its vehicles were clearly marked as belonging to Save the Children.
The Sudanese government blamed the shooting on the Sudanese Liberation Army.
It happened between Mershing and Duma, on the road linking Nyala and the main town in north Darfur, El Fasher.
Radhia Achouri, a spokesperson for the UN in Sudan, expressed regret for the deaths but denied an Associated Press report that the UN too had suspended its operations in south Darfur.
She said that some roads were no-go areas for the UN but this had been the case before the killings.
Ken Caldwell, director of Save the Children’s international operations, said: ”We deplore this brutal killing of humanitarian workers in Darfur. Our deepest sympathies are with the family and friends of our Sudanese colleagues.”
International monitors from the African Union, which is trying to maintain a ceasefire between the government and the rebels, recovered the bodies and are investigating the deaths.
Save the Children operates food centres and clinics in the Mershing and Duma areas.
An aid worker was shot on the same road in the summer but survived. In October, two Save the Children workers were killed in north Darfur by a landmine.
The organisation only recently resumed its operations in north Darfur, suspended after a bomb from a government plane landed near one of its clinics.
Relations between the government and the aid agencies have been strained in the past year, initially because of the government’s delay in issuing its staff with visas to work in Darfur, and in allowing aid shipments to enter the region.
A fortnight ago, the government threatened to expel senior staff of Save the Children and Oxfam, claiming that they had been making political statements.
Save the Children had been complaining about the bombing incident.
Although that threat appears to have been shelved, the head of Oxfam in the Sudan, Shaun Skelton, was forced to leave the country last week after a visa row. The government claimed that he was working in Khartoum but had a visa only for Darfur. He is in neighbouring Kenya applying for a new visa.
There are almost 6 000 aid workers in Darfur, of whom about 800 are from outside Sudan; the rest have been recruited locally.
The United Nations Secretary General, Kofi Annan, said last week that Darfur was in chaos, subject to banditry, rape and village burnings, and 2,3-million people were in need of aid.
The World Health Organisation estimates that 70 000 people have died in Darfur since March.
Only 900 of the 3 300 monitors promised by the African Union are in place.
Britain has provided them with 143 vehicles.
The singer Fran Healy travelled with Save the Children to Darfur on Saturday, where he is spending the week visiting projects funded by proceeds from the Band Aid single. – Guardian Unlimited Â