The Red Cross has suspended its operations in Sudan following orders from government authorities.
The work was halted for some "technical issues" associated with pending projects in the country, the agency said.
"We have received an official letter from the HAC (Humanitarian Aid Commission) informing us to suspend our activities with effect from today," Rafiullah Qureshi, spokesman for Red Cross in Sudan, told AFP.
Over the past four decades, the International Committee of the Red Cross (ICRC) has worked in collaboration with local authorities and central government entities, including the Humanitarian Aid Commission (HAC) for internal displacement.
The ICRC is known in the country for assisting in repatriation of prisoners and civilians held by armed groups in areas ravaged by war in western Sudan.
"We help people affected by the conflict in Darfur, provide seed, tools, food and water, and re-establish contact between people separated by the fighting," the ICRC says on its website.
"The ICRC also promotes international humanitarian law and the protection of civilians affected by the conflict."
Despite the suspension of operations, the ICRC's local staff is expected to hold discussions with the foreign ministry and other government agencies over the coming days.
The aim of the talks will be "to resume our activities as soon as possible in favour of the victims of armed conflict," Qureshi said.
Access is already restricted in rebel-held South Kordofan and Blue Nile regions, where more than one million people have been displaced in the last two years.
The Sudanese government has also banished aid agencies from the country in the past.