Sudan's army has denied bombing a World Food Programme (WFP) convoy taking aid to a famine-hit area in the country's Darfur region.

The paramilitary Rapid Support Forces (RSF) had blamed the army for Wednesday's air strike in the town of Mellit, which is under RSF control.

A UN agency said a drone hit the convoy, and three lorries in the 16-vehicle convoy caught fire and were destroyed. All staff travelling in the convoy were safe, it added.

Sudan plunged into a civil war in April 2023 after a vicious power struggle erupted between the army and the RSF, creating one of the world's worst humanitarian crisis.

The RSF does not have an air force, but both sides use drones.

The attack is the latest in a string of assaults on humanitarian operations in Sudan.

"Humanitarian staff and assets must never be a target," the WFP said, urging the warring parties to respect international humanitarian law.

The convoy was headed towards a village near Mellit, a "famine-affected area" some 90km (56 miles) north-west of el-Fasher, the WFP said. The city, the army's last foothold in the Darfur region, has been besieged by the RSF for more than a year.

It is one of the main areas of conflict in the civil war, and the RSF has intensified its battle for control of el-Fasher in recent weeks.

Both sides have previously been accused of using starvation as a weapon of war by obstructing the delivery of aid and looting food.

Five aid workers were killed in a similar attack in el-Fasher in June.

Tens of thousands of people have died, and 12 million have been forced from their homes because of the conflict.

More than 4.5 million refugees, mostly women and children, have fled to neighbouring countries.