The Sudanese army said in a statement on Tuesday that its forces have withdrawn from positions in Wad Madani city, adding that it will investigate the reasons for the withdrawal.
Sudan's paramilitary Rapid Support Forces (RSF) took over Wad Madani, a city packed with displaced people and an aid hub, earlier this week.
The war between the army and the RSF has displaced nearly 7 million people, left the capital in ruins, caused a major humanitarian crisis and triggered waves of ethnically driven killings in Darfur.
The two forces had shared power with civilians after the 2019 overthrow of former leader Omar al-Bashir before staging a coup together in 2021 then coming to blows over an internationally backed political transition plan.
The International Organization for Migration says that clashes between the RSF and the army around Wad Madani have led to widespread displacement in recent days.
Nearly 1.5 million have fled Sudan and more than 5.4 million have been forced from their homes internally, according to the IOM, making Sudan the country with the highest number of displaced people in the world.