"The government of South Africa decided to withdraw its troops from the mission," said the official, who spoke on condition of anonymity.
The 850 troops will end operations on April 15.
"Of course, we will have to look at the contingency in terms of how we fill those gaps," she said.
Relations between Sudan and the United Nations have been tense over Khartoum's demands that the 17,000-strong UNAMID peacekeeping mission shut down.
South Africa's decision to pull out comes after five weeks of intense fighting that have sent some 85,000 people fleeing in the Jebel Marra area while UN officials are seeking to verify reports of an additional 50,000 on the move.
The 85,000 civilians, mostly women and children, have fled to north Darfur, but UN officials are seeking access to central Darfur where unconfirmed reports suggest 50,000 people have been driven from their homes there.
The Khartoum government has denied access to UNAMID, said the official.
A large influx of 63,000 civilians taking refuge at the UNAMID camp set up at Sortoni, in north Darfur, is prompting concerns.
"We are very concerned by the swelling of the makeshift camp at Sortoni. 63,000 people is a large number of civilians," said the official.
Sudan's army has been trying to crush rebels of Abdulwahid Nur's faction of the Sudan Liberation Army (SLA-AW) in Jebel Marra, saying it was responding to attacks by the rebels.
The UN says that some 300,000 people have been killed in the fighting in Darfur since 2003 and 2.5 million displaced.
You’ve reached your limit of {{free_limit}} free articles this month.
Subscribe now for unlimited access.
Already subscribed? Log in
Subscribe to read the full story →
Smart Quarterly
₹900
3 Months
₹300/Month
Smart Essential
₹2,700
1 Year
₹225/Month
Super Saver
₹3,900
2 Years
₹162/Month
Renews automatically, cancel anytime
Here’s what’s included in our digital subscription plans
Exclusive premium stories online
Over 30 premium stories daily, handpicked by our editors


Complimentary Access to The New York Times
News, Games, Cooking, Audio, Wirecutter & The Athletic
Business Standard Epaper
Digital replica of our daily newspaper — with options to read, save, and share


Curated Newsletters
Insights on markets, finance, politics, tech, and more delivered to your inbox
Market Analysis & Investment Insights
In-depth market analysis & insights with access to The Smart Investor


Archives
Repository of articles and publications dating back to 1997
Ad-free Reading
Uninterrupted reading experience with no advertisements


Seamless Access Across All Devices
Access Business Standard across devices — mobile, tablet, or PC, via web or app
