"I was deeply saddened today to learn that a member of the United States Agency for International Development’s [USAID] Disaster Assistance Response Team was shot and wounded early this morning in Darfur," Condoleezza Rice, US secretary of state, said in a statement read by spokesman Adam Ereli on Tuesday.

"The thoughts and prayers of all of us at the Department of State and USAID are with her and her family as she continues to receive treatment," Rice added.

Jan Pronk, the UN special envoy to Sudan condemned the attack. In a statement on Wednesday, Pronk said such incidents were unlikely to stop unless a robust protection force of at least 8,000 troops was deployed in Darfur to protect both the civilian population and humanitarian workers.

In a statement released the same day, the Sudanese Ministry of Foreign Affairs expressed deep regret over the incident, and "strongly condemned the unjustifiable attack on the relief convoys and workers of humanitarian aid in Darfur."

The Sudanese government, it added, would make every effort to secure the flow of humanitarian aid and to ensure the safety of all humanitarian workers. It promised that the appropriate authorities would immediately investigate the incident and pursue the culprits.

On 21 December 2004, the international relief organisation Save the Children UK (SC UK) withdrew its staff from Darfur after four were killed. They included two Sudanese who were killed when they came under fire on 13 December in South Darfur.

Earlier on 10 October, two other SC UK workers, a British programme manager and a Sudanese water engineer, were killed by a landmine in North Darfur, while their driver was seriously injured. The African Union later blamed rebel forces for the landmine incident.

Only last week, the UN Advance Mission in Sudan (UNAMIS) expressed concerns about the sharp rise in armed attacks against humanitarian operations across Darfur since the second week of March.

Numerous incidents reported included armed robbery, the harassment of aid workers, the ambushing of vehicles at gunpoint, and the looting of the vehicles’ contents as well as passengers’ personal belongings, UNAMIS spokeswoman Radhia Achouri said.

In his Darfur report to the UN Security Council, released on 12 March, UN Secretary-General Kofi Annan warned that, as a result of the increasing harassment of NGOs since the end of 2004, greater pressure had been placed on humanitarian operations.

"Commercial trucks carrying humanitarian assistance, including those marked as agency or humanitarian affiliated, continue to be attacked by armed groups on major routes, severely limiting access to populations and causing major delays in the critical timely delivery of essential items, particularly food," Annan said.