The eight tonnes of aid contains surgical material for Sudanese hospitals and volunteers from the Sudan Red Crescent Society, including anaesthetics, dressings and sutures.

Patrick Youssef, ICRC regional director for Africa, said: "Healthcare workers in Sudan have been doing the impossible, caring for the wounded without water, electricity, and basic medical supplies.

"The logistics needed to bring in supplies amid an active conflict are extremely difficult, and we're relieved to get this medical material into the country."

The UK government said on Sunday that another evacuation flight would be offered to Britons on Monday.

Those hoping to leave the country should be at the British Evacuation Handling Centre at Port Sudan International Airport before midday on that day.

The ICRC is understood to be sending a second plane carrying further medical supplies and emergency personnel.

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It comes as the Sudanese army said it had agreed to extend a truce with the paramilitary Rapid Support Forces (RSF) for 72 hours from the end of the current ceasefire arrangement.

Earlier on Sunday, the rival military forces accused each other of fresh violations of the ceasefire.

Hundreds of people have been killed and thousands wounded since a long-simmering power struggle between the Sudanese army and the paramilitary RSF erupted into conflict on 15 April.

The Sudanese army said it had destroyed RSF convoys moving towards the capital Khartoum from the west.

The RSF said the army had used artillery and warplanes to attack its positions in a number of areas in Khartoum province.

Neither of these claims have been independently verified.