"Whether it is Darfur, South Kordofan or Blue Nile, what is needed above all else is for the fighting to stop and for the conflicts to be resolved by peaceful means," Undersecretary-General for Humanitarian Affairs Valerie Amos said in a release.
The situation is "extremely worrying," Amos said from Khartoum after a four-day visit to Sudan and the Darfur region.
"After 10 years of major humanitarian operations in Darfur, we need to find more sustainable ways of supporting displaced people who have no other option but to remain in the camps. We need to build stronger bridges between humanitarian and development work," Amos said.
Amos said a woman living in a camp near El Fasher told her she "feels like a bird in a cage."
The U.N. official said thousands of children born in the internally displaced persons camps "have never known life outside these camps. We cannot forget these children. They are the future of Darfur and of Sudan."
In April, a Darfur Donors Conference raised $3.6 billion in pledges for Darfur, including a commitment of $2.6 billion from the government of Sudan.
While welcoming the commitments, Amos said Sudan still has a "serious funding crisis," needing an estimated $7.2 billion for a multiyear, U.N.-backed effort to move away from food handouts and other emergency aid.
She said she had "very constructive and informative meetings" with Sudanese President Omar al-Bashir and other senior government officials, and representatives of U.N. member countries, agencies, non-governmental organizations and humanitarian partners.