The United States on Wednesday implored Sudan's authorities to let aid into the country, denouncing holdups as the war between rival generals leaves millions in need of help.
Samantha Power, administrator of the US Agency for International Development, said that funding for Sudan's crisis "remains shockingly low," with around 25 million people, or more than half of the population, in need of assistance.
But she said that even the aid that arrives faces obstacles due to "ill-disciplined or rapacious" forces on the ground, and bureaucracy "mastered through decades of practice at being obstructionist."
"Sudan continues to present some of the toughest conditions for humanitarian access in the entire world, and that is saying something," she said at the US Institute of Peace.
"Unconscionably, supplies are actually there - stuck at the border or in the Port of Sudan as permits to move aid into the country continue to be denied," she said.
"The fact that a permit could stand in the way of supplies reaching people with life-or-death needs and conditions is horrifying," she said.
Power said that small-scale local and diaspora groups have filled the vacuum and acknowledged that USAID took "far too long" to channel assistance through them.
"If these relief networks were to collapse, millions of Sudanese civilians would be left with no assistance at all. To prevent that from happening, these groups need more resources," she said.
The United States in September announced $130 million in new assistance to Sudan.