"The deadly attack resulted in the death of 15 people with six others injured and two individuals still missing," said the Emergency Lawyers, who have been documenting human rights abuses throughout the 20-month war between the army and paramilitary Rapid Support Forces (RSF).

Most of Omdurman -- the capital's twin city across the Nile River-- is under army control, but Saturday's attack occurred in western Omdurman, which is under RSF control.

The truck, which was carrying milk barrels from surrounding villages to an area near a camel market in Omdurman, reportedly broke down on the road before being targeted by the military drone, the lawyers said.

They added that according to initial evidence, the victims were all herders and workers involved in milk transportation.

Tens of thousands of people have been killed in the war which has left the northeast African country on the brink of famine, according to aid agencies.

Both the army and the RSF have been accused of targeting civilians, including health workers, and indiscriminately shelling residential areas.

The RSF holds Khartoum North (Bahri) just across the Nile River and also part of the greater Khartoum area.

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