"Shells fell on the Al-Nau hospital," in Omdurman, the twin city of Sudan's capital Khartoum, a medical source told AFP by telephone.
Omdurman has been the site of fierce battles between the regular army led by General Abdel Fattah al-Burhan and the paramilitary Rapid Support Forces (RSF) commanded by his former deputy Mohamed Hamdan Daglo who have been at war since April.
Rights groups have accused both sides of targeting health facilities since the conflict began on April 15.
In August, medical aid group Doctors Without Borders (MSF) warned that Al-Nau hospital "is one of the last health facilities open in Omdurman."
"It's also the only facility with a trauma emergency room or surgical capacity in north Omdurman, so all wounded patients in the city are brought there," MSF said, while other medics have called the hospital "a beacon of hope."
According to the United Nations, more than 70 percent of the country's hospitals are out of service.
Though most of the fighting was previously contained to the capital and the western region of Darfur, it has also spread to areas south of Khartoum according to witnesses.
In Jabal Awliya town, 50 kilometers (31 miles) south of the capital, medics "have had to halt all work at the hospital since last night due to heavy artillery shelling," a doctor told AFP.
"Dozens of wounded" remained in the hospital, waiting for urgent treatment, he added.
More than 9,000 people have been killed in the Sudan conflict so far, according to a conservative estimate by the Armed Conflict Location & Event Data project.
But aid groups and medics have repeatedly warned the real toll exceeds recorded figures, with many of those wounded and killed never reaching hospitals or morgues.
Monday's shelling comes a day after fighting resumed in El Obeid, the state capital of North Kordofan 350 kilometers south of Khartoum.
One child was killed and at least 16 injured in the fighting while some homes were destroyed, a committee of pro-democracy lawyers that have worked to document atrocities said.
The war has caused an estimated 5.5 million people to flee, both within Sudan and across borders, according to the United Nations.
Sudan Shelling Hits Hospital
WAD MADANI, SUDAN - At least three civilians were killed on Monday in Sudan when shells struck a key hospital in the capital, a medical source said, as fighting between rival generals continued unabated.
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