JAKARTA, Indonesia – Australia promised $764 million – the largest government pledge – to the tsunami relief effort, topping a $674 million German aid package on the eve of a crucial donors’ conference today. World leaders were competing to head the donors’ list as summit participants got firsthand looks at the apocalyptic landscapes carved out by south Asia’s tsunami.

Secretary of State Powell, a battle hardened veteran of the Vietnam War, was aghast at the devastation on Indonesia’s Sumatra Island. “I’ve never seen anything like this,” he said.

India has politely turned down the unprecedented offers of money and military might, but many Indonesians appeared to be putting pride aside: During Mr. Powell’s visit, survivors expressed gratitude for American aid.

“Thank God he’s come. Thank God,” said Mohamed Bachid Madjid, peering from a bridge into the Aceh River, where two bloated corpses floated among the flotsam.

The fresh outpouring of generosity appeared at times to be almost like a bidding war and raised questions about whether rich nations were using the tragedy to jockey for influence on the world stage and with hardest-hit Indonesia, which has a wealth of natural resources.

The European commissioner for development and humanitarian aid, Louis Michel, urged donors not to engage in one-up-manship. “We have to be careful and not participate in a beauty contest where we are competing to give higher figures,” he said.

But U.N. humanitarian chief, Jan Egeland, the man who riled Washington by complaining that wealthy nations were often “stingy,” said Tuesday: “I’d rather see competitive compassion than no compassion.”

Mr. Michel also said too many countries were making pledges that may not be honored.

A little over a year ago, donors promised Iran more than $1 billion in relief after an earthquake killed 26,000 people there. Iranian officials say only $17.5 million has been sent.

The pledges yesterday by Australia and Germany pushed the total relief sum above $3 billion for the 11 countries hit by killer waves whipped up by a massive earthquake on December 26.

Mr. Egeland, at the United Nations, called the two countries’ pledges “phenomenal” and said the offers were so large that his staff members had to ask donors to repeat what they said to make sure they heard the number of zeroes correctly.

Australia initially set its aid pledge at $810 million, but that included funds earmarked for Indonesia before the tsunami. Australian officials said new money promised amounts to $764 million. Most of the pledge is for neighboring Indonesia.

“Out of the appalling tragedy of the tsunami has emerged an opportunity to build a new future,” Prime Minister Howard said.

America was the first to raise the stakes dramatically in the aid race by pledging $350 million on Friday; it now lies fourth on the donor list and has sent in two aircraft carrier groups and thousands of troops. Japan last week promised a $500 million package.

The death toll of Americans from the tsunami more than doubled yesterday, to 36, as the State Department announced 20 other American citizens were presumed dead.

Thousands more are unaccounted for, but the State Department does not believe anywhere near that number are dead.

President Bush, who has pledged $350 million in American aid to help disaster victims, has personally contributed $10,000 to the relief effort, his spokesman said yesterday.

The donors’ conference was focusing on how best to allocate the billions in aid following a disaster that wiped out villages and infrastructure, left millions homeless and threatened with disease, and killed more than 139,000 people. Leaders also were to discuss a warning system to prevent massive death tolls from future tsunamis.

The World Health Organization said it urgently needs $60 million to provide safe drinking water, sanitation, shelter, food, medical, and other supplies to prevent disease outbreaks that would put another 150,000 people at “extreme risk” of dying. The United Nations announced that camps for up to 500,000 tsunami refugees will be built on Sumatra.