The record generosity toward tsunami (search) victims — now at more than $4 billion pledged — should set the standard for caring for the world's most desperate people, the U.N. humanitarian chief said Tuesday. But aid group Oxfam (search) said it fears the money might simply be rerouted from existing funds for Africa.

Jan Egeland (search), U.N. undersecretary-general for humanitarian affairs, said a new outside auditing system will not only prove a further guard against any misuse of funds given to the United Nations, but will also make sure governments meet their pledges.

"We are seeing an extraordinary effort, probably unique in the history of humankind," Egeland said after an 81-nation meeting with ministers and other officials.

Both Indonesia and Sri Lanka tried Tuesday to defuse tensions with insurgencies to make sure aid efforts aren't disrupted on the ground.

Indonesia offered a cease-fire to rebels in Aceh province, the area hardest-hit by the Dec. 26 earthquake and tsunami that killed more than 150,000 people. A rebel spokesman said the offer was a positive step even if it was late in coming.

In a gesture apparently aimed at helping mend the rift between warring communities in Sri Lanka, President Chandrika Kumaratunga — an ethnic Sinhalese — announced plans to adopt a child from the disgruntled Tamil minority orphaned by the tsunami.

So far, governments and international development banks have pledged more than $4 billion to aid 5 million tsunami victims across the region. That figure does not include private contributions to many charities.

"We do not yet have the cash in hand required to meet even the most urgent needs," Egeland said. "We are in a race against time and we need cash now if we are going to provide assistance to all in need during the next six months."

Egeland said $717 million has been converted from pledges to binding commitments.

But some donors have failed to make good on their promises after past disasters, and aid groups say they will keep the pressure on to make sure the help recently announced with great fanfare doesn't evaporate.

For example, donors promised more than $1 billion after an earthquake killed 26,000 people in Bam, Iran, in December 2003. A year later Iran says it's gotten only $17.5 million.

Even if all the pledges are honored, Oxfam said it fears money earmarked for African relief may be shifted to Asia and urged countries to confirm that their donations would be "new" money, not taken from another aid project.

"At the moment we're looking at Germany, who have confirmed that all of the money that they're pledging is new money," Oxfam spokeswoman Amy Barry said. "Nobody else has done that so far."

European aid commissioner Louis Michel agreed. "It wouldn't be right to deal with this tragedy by cutting assistance for Africa or other regions of the world in the grip of permanent humanitarian crises."

Donor countries should have the same generosity to all victims, he said.

"The world has never been richer," Egeland said. "It should be possible to feed those 20 to 30 million people in desperate need of assistance."

He noted that the United Nations has accepted an offer from outside accountants to track operations. The system proposed by PricewaterhouseCoopers "will make donors accountable for honoring their pledges and hold the United Nations accountable for disbursing the money and for doing a good job in the field."

"We will also work on a system of immediate investigation of all possible, alleged mishandling of funds," Egeland said. "We cannot afford any question marks on whether or not there is an effective use of this unprecedented generosity."

Heidemarie Wieczorek-Zeul, Germany's development aid minister, said the accounting plan would help maximize the relief effort.

"There must be transparency on both sides," she said.

French Deputy Foreign Minister Renaud Muselier said donors need to stick by tsunami-affected countries for years to come — even when the high-profile disaster has slipped from the headlines.

"The rhythm of images and emotion doesn't necessarily tie in with the rhythm of reconstruction," he said.

Andrew Natsios, the administrator for the U.S. Agency for International Development, said the United States would consider raising its $350 million pledge after the United Nations has put together a comprehensive budget.

"We will make our own assessment as to whether more money will need to be donated by the United States."