BANDA ACEH, Indonesia - Indonesian authorities warned aid workers today that many parts of tsunami-battered Aceh province were not safe for foreigners, and the military claimed rebels were trying to rob aid convoys. A man drifting at sea for two weeks said he survived on coconuts and bottled water he found on a raft.

Indonesia's government said the airport in Banda Aceh, the provincial capital and hub of relief operations, was dangerously overstretched, and the U.N. and 80 donor nations meeting in Geneva studied how to best use $4 billion in tsunami aid.

As the challenges mounted amid an unprecedented global relief effort, the United Nations made the unusual move of turning to an outside accounting firm to help track the billions in aid money and investigate any credible allegations of fraud, waste or abuse.

A Dec. 26 earthquake and the giant waves it spawned killed more than 150,000 people in Asia and Africa - roughly two-thirds of them in Indonesia.

In Sri Lanka, where 30,000 people died, the nation's president urged her countrymen not to make hasty attempts to rebuild homes along the shattered coast, saying the government would help them move inland.

President Chandrika Kumaratunga, who is from the Sinhalese majority, also said she plans to adopt a Tamil child orphaned by last month's tsunami - a startling gesture that appeared to be aimed at helping mend a three-decade rift between the two warring communities.

Hardest hit by the disaster was Indonesia's Aceh province, another region long wracked by rebellion. Military chief Gen. Endriartono Sutarto said today that separatists, who have been fighting government troops for more than 20 years, were trying to hijack relief supplies.

He called on them to agree to a cease-fire and "work together" to help rebuild.

"If they ask for food, we will give it to them," he said. "They do not have to do this."

Asked if some places were unsafe for foreign aid workers, Aceh relief operations chief Budi Atmaji said at a news conference: "Yes, in some places."

The military asked aid groups to draw up a list of international relief workers - and to report on their movements - but has yet to offer evidence backing the claims.

The rebels, through a spokesman in Sweden, deny they are threatening aid distribution and say their supporters are among the thousands of victims of the disaster in need of help.

Across the region, tens of thousands of people are homeless and threatened by the disease, and health officials have warned that the death toll from the tsunami disaster could double if aid does not reach the neediest fast enough.

The refugee camp in Calang, Indonesia, has grown so fast that considerations like sanitation and preserving clean sources of water have been left behind, meaning conditions such as diarrhea are becoming rampant and raising the threat of other diseases, doctors said.