Sudanese paramilitaries killed at least 17 civilians Tuesday in northern Khartoum, a medical source said, as the United Nations warned the conflict between two rival generals has "broken the nation".

Witnesses reported shelling by the paramilitary Rapid Support Forces in the Karary district of Omdurman, a part of greater Khartoum that has seen fierce battles between the RSF and the regular army.

A medical source told AFP "17 civilians were killed" in the attack, five months into the conflict between the army under General Abdel Fattah al-Burhan and RSF commanded by his former deputy, Mohamed Hamdan Daglo.

Nearly 7,500 people have been killed in Sudan since the conflict broke out on April 15, according to a conservative estimate from the Armed Conflict Location & Event Data project.

"In the past week, more than 103 civilians have been killed during military operations by both parties in Khartoum and Omdurman," UN human rights chief Volker Turk told the Human Rights Council in Geneva on Tuesday.

On Sunday, at least 51 people were killed and dozens wounded in air strikes on a southern Khartoum market, Turk reported, in one of the deadliest single attacks since fighting began.

According to activists, a dozen bodies were unidentified and -- like many of those killed on the street and missing from their families -- buried by volunteers in shallow graves.

Diplomatic efforts in the early months of the war repeatedly failed to achieve a sustained ceasefire, and the violence shows no signs of abating.

"There is no reprieve in sight," Turk said, listing the horrors reported by civilians, including "stories of family members being killed or raped, of their relatives being arrested without reason, of disappeared loved ones, of piles of abandoned bodies, of desperate, lingering hunger."

The war has caused a humanitarian catastrophe in what was already one of the world's poorest countries, where the UN now warns six million people are on the brink of famine.

Turk also called for accountability for violations committed by both sides, including "widespread arbitrary detention".

"Hundreds -- and likely thousands -- are being held incommunicado in appalling conditions," he added.

The war has also uprooted more than five million people, including one million who fled across borders, according to United Nations figures.