The Emergency Lawyers said Monday's air strike 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 from the paramilitary Rapid Support Forces (RSF) since May.

Tens of thousands have been killed and millions displaced in a 20-month war between the RSF and Sudan's army that has left the northeast African country on the brink of famine, according to aid agencies.

"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", though the military denied it had carried out the attack.

The army said in a statement the accusations were "lies" spread by political parties backing the RSF, adding that it would continue "exercising its legitimate right to defend the country".

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

The footage was supplied by civil society group the Darfur General Coordination of Camps for the Displaced and Refugees and AFP has not been able to verify its accuracy.

The lawyers group said in a separate incident on Monday evening three neighbourhoods were hit with barrel bombs in Nyala, the capital of South Darfur, without reporting casualties.

Darfur, a region the size of France, is home to around a quarter of Sudan's population but more than half of its 10 million are displaced.

A UN-backed report in July said famine had taken hold in a major refugee camp in North Darfur after a months-long RSF siege disabled nearly all trade and aid access.

- 'Escalation campaign' -

The lawyers group flagged other incidents around Sudan including one in North Kordofan state where a drone that had crashed on November 26 exploded on Monday evening, killing six people.

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.