Sudan had said it needed $6.1 billion up to 2011, on top of $2 billion in humanitarian aid, but a deadly aerial bombing in Darfur three days ago cast a shadow over the Oslo conference.

"As we are tallying up the figures, it stands at $4.8 billion," Hartwig Schafer, a senior World Bank official, told the conference.

Officials said the aid should help Sudan continue to implement the 2005 comprehensive peace agreement (CPA), which ended the longest civil war in Africa.

"The implementation of the CPA is more critical than ever. The CPA will benefit not only the Sudanese, it will have ripple effects throughout the region," Schafer said.

Asraf Qazi, special representative of the U.N. Secretary General for Sudan, said: "(This) has indeed been a success. While CPA implementation has fallen behind schedule, the fact is that it remains on track and your contribution will help."

Britain, which pledged $650 million in assistance to Sudan on Wednesday, said it hoped that the bulk of its funds would be used for development, not only immediate humanitarian efforts in Darfur and other regions hit by sky-rocketing food prices.

"The extent to which these funds can be used for development will depend crucially on resolution of the Darfur crisis," said Dave Fish, head of the British delegation to a donors' conference in the Norwegian capital.

Diplomats at the conference condemned Sunday's government bombing attack on a school and marketplace in Darfur, which killed 12 including six children and wounded 30.

Some said it could make countries reluctant to pledge openly before a satisfactory explanation.

"We now spend two-thirds of our money on humanitarian assistance, and we are desperately keen to shift the balance of that activity to recovery and development," Fish told Reuters.

"But as long as things carry on as they are in Darfur and one or two other places, it makes that very difficult," he said.

Fish said the aerial bombing was "appalling" and the timing "crass in relation to this consortium, and it probably derives from splits in the government in Khartoum".

International experts estimate 200,000 have died and 2.5 million have been driven from their homes in five years of revolt in Darfur. Sudan puts the death toll at about 10,000.