The paramilitary Rapid Support Forces began its offensive on Sennar province during the week, attacking the village of Jebal Moya before moving to the city of Singa, the provincial capital, where fresh battles have erupted.
The group claimed in a statement on Saturday it had seized the military's main facility, the 17th Infantry Division Headquarters, in Singa.
"When I sleep, I remember the sound of bombs, and I wake up frightened." - Dania, 5.— UNICEF (@UNICEF) Find out how the brutal war in Sudan is exacting a heavy price on the mental health of children like Dania. https://t.co/PVYVXL712RJune 30, 2024
Local media also reported the Rapid Support Forces managed to breach the military's defence.
However, Brigadier Nabil Abdalla, a spokesman for the Sudanese armed forces, said the military regained control of the facility, and that fighting was still under way on Sunday morning.
Neither claim could be independently verified.
According to the United Nation's International Organisation for Migration, at least 327 households had to flee from Jebal Moya and Singa to safer areas.
"The situation remains tense and unpredictable," it said in a statement.
Residents reported widespread looting of homes and shops in Singa by paramilitary fighters who seized private vehicles, mobile phones, jewellery and other valuable possessions.
"They did like what they did in (the capital) Khartoum and other cities," said Abdel-Rahman al-Taj, a Singa resident who fled Saturday to Blue Nile province.
"Many people were killed, wounded or detained."
The Sennar Observatory for Human Rights, a local rights group, said the paramilitary forces attacked Singa Educational Hospital, detaining dozens of patients and medical staff as "human shields".
The 14-month war in Sudan has pushed the African nation to the brink of famine. (AP PHOTO)
The fighters turned the hospital into a military centre in a "clear violation of the international human material law".
The Rapid Support Forces did not immediately respond to a request for comment.
The paramilitary group has been repeatedly accused of gross rights violations across the country since the war started in April 2023, when simmering tensions between the military and the paramilitary exploded into open fighting in Khartoum and elsewhere.
The fighting in Sennar comes while attention has been focused on al-Fasher, a major city in the sprawling region of Darfur that the paramilitary has besieged for months in an attempt to seize it from the military.
Al-Fasher is the military's last stronghold in Darfur.
The devastating conflict has killed more than 14,000 people and wounded 33,000, according to the UN, but rights activists say the toll could be much higher.
It created the world's largest displacement crisis with more than 11 million people forced to flee their homes.
International experts warned on Thursday that that 755,000 people are facing famine in the coming months, and that 8.5 million people are facing extreme food shortages.
The conflict has been marked by widespread reports of rampant sexual violence and other atrocities - especially in Darfur, the site of a genocide in the early 2000s.
Rights groups say the atrocities amount to war crimes and crimes against humanity.
