The Emergency Lawyers said the air strike on Monday also left hundreds injured in Kabkabiya, a town about 180 kilometres (112 miles) west of El-Fasher, the state capital that has been under siege by the paramilitary Rapid Support Forces (RSF) since May.

The war between the RSF and the regular army has so far killed tens of thousands, uprooted over 11 million and created what the United Nations has called the worst humanitarian crisis in recent memory.

"The air strike took place on the town's weekly market day, where residents from various nearby villages had gathered to shop, resulting in the death of more than 100 people and injury of hundreds, including women and children," said the lawyers' group, which has been documenting human rights abuses during the conflict.

They described it as a "horrendous massacre committed by army air strikes".

In footage sent to AFP purporting to show the aftermath of the strike, people were seen sifting through rubble as the charred remains of children lay on scorched ground.

The footage, which AFP was unable to independently verify, was supplied by civil society group the Darfur General Coordination of Camps for the Displaced and Refugees.

Though some drone attacks have been attributed to the RSF, the Sudanese military is the only party with fighter jets and maintains a functional monopoly on the skies.

In a statement Tuesday, the army accused RSF-affiliated political groups of "spreading lies" and said its forces "target rebel activity bases".

- Bus shelled -

Darfur, a region the size of France, is home to around a quarter of Sudan's population but more than half of the country's displaced population.

Nearly all of it is now controlled by the RSF, which has also taken over swathes of the southern Kordofan region and central Sudan, while the army holds the country's north and east.

Both forces are wrestling for full control of the war-torn capital, 1,000 kilometres (621 miles) east of El-Fasher.

In Omdurman, part of greater Khartoum, paramilitary artillery fire on a passenger bus killed at least 15 people, a medical source told AFP.

The Al-Nao hospital, one of the last facilities receiving patients in the area, also "received 45 injured from different areas", the source said, requesting anonymity for fear of reprisals.

"We haven't seen bombing this intense in six months," one eyewitness to the passenger bus shelling told AFP, also requesting anonymity.

Most of Omdurman is under army control, while the RSF holds Khartoum North (Bahri) just across the Nile River.

Residents have continuously reported shelling across both sides of the river, with bombs and shrapnel regularly striking homes and civilians.

According to the United Nations, up to 80 percent of health facilities in Sudan's worst affected areas are barely operational or closed.

- 'Escalation campaign' -

The lawyers' group flagged other incidents around Sudan including one in South Darfur state capital Nyala, where they said three neighbourhoods were hit with barrel bombs on Monday evening.

They could not confirm a toll.

In North Kordofan state, a drone that had crashed on November 26 exploded on Monday evening, killing six people, the lawyers reported.

They said recent strikes across the country were part of an "escalation campaign... deliberately concentrated on densely populated residential areas", contradicting claims by warring parties that they only target military objectives.

Both the army and the RSF have been accused of indiscriminately targeting civilians and deliberately bombing residential areas.

On Tuesday, Human Rights Watch accused the RSF and allied Arab militias of carrying out numerous abuses against civilians in South Kordofan state from December 2023 to March 2024.

The rights organisation accused the groups of "war crimes" including "killings, rapes, and abductions of ethnic Nuba residents, as well as the looting and destruction of homes".

The group also urged the United Nations and the African Union to deploy a mission to protect civilians in Sudan.