A fraction of available aid has passed through the Adre border crossing from Chad into Sudan's hunger-ravaged Darfur region this week following a move by the Sudanese army to temporarily lift a ban on deliveries.

The army's rivals in the country's devastating 16-month-old war control most of Darfur and the Adre crossing, the quickest way into the region. The army had ordered aid agencies to stop use of the corridor in February, saying it was used to transport arms, but last week rescinded that order temporarily for three months.

After 15 trucks had moved through the crossing, out of a total of 131 at the border, the Sudanese government "instructed no more movements until procedures received yesterday are agreed," Justin Brady, head for the UN's Office for the Coordination of Humanitarian Affairs in Sudan, said on X late on Wednesday.

In a statement on Wednesday, the World Food Programme said that sorghum, pulses, oil and rice enough for 13,000 people had crossed on Tuesday evening, heading for Kreinik, West Darfur, one of 14 spots across the country experts say is at risk of famine.

But, the agency said, it had food for 500,000 ready to move. More than six million people face food insecurity across Darfur, and more than 25 million, or about half the population, across the country.

It was unclear if the food had reached Kreinik by Thursday. The RSF, which has looted aid trucks and warehouses on numerous occasions according to aid agencies, welcomed the deliveries in a statement late on Wednesday.

A document by the army-aligned Humanitarian Aid Commission showed that the procedures set by the government included the presence of Sudanese authorities and soldiers at Chadian warehouses and the border for inspections.