With more than 125,000 confirmed dead from the first tidal wave in recorded history to hit several countries at once, the United Nations said the toll may be nearing 150,000 and that the true count may never be known.

"I think we are now seeing a significant and welcome outpouring of support from the international community," Powell told a joint press conference with the UN chief after their meeting.

"This is an unprecedented disaster," Powell said. "I hope that the world will be generous."

Amid press reports about a rivalry between the United Nations and the United States over who would take the lead role in the relief campaign, both men said that the world body was leading the effort.

Annan underlined "the need for us to cooperate and coordinate our efforts as effectively as possible" and stressed the immediate need was now for logistical support, including aircraft, to get supplies in as quickly as possible.

Powell was due to head to Asia this weekend for a first-hand look at the devastation that Annan again warned will require a long-term commitment from the international community to address.

US President George W. Bush earlier upped the United States contribution tenfold to 350 million dollars, which put the total so far to more than 1.1 billion dollars.

"We are now counting new pledges by the hour. We're now between 1.1 billion and 1.2 billion dollars," said the UN's emergency relief coordinator, Jan Egeland.

Powell said the US contribution could still rise.

"This tenfold increase is indicative of American generosity but it is also indicative of the need," he said.

But as the pledges rolled in, Annan stressed that getting access to the battered regions was a crucial concern as relief workers battle to save the lives they still can.

"Obviously we are concerned. We would want to get to everybody as quickly as we can," Annan said. "It's a race against time and we are pressing ahead, trying to do it as fast as we can."

Both men said the principal focus of efforts would be Indonesia, which has emerged as the country worst affected by Sunday's huge earthquake off its western Sumatra island and the tidal waves the quake spawned.

"What we see is that the figures may be approaching 150,000 dead. The vast majority of those are in Indonesia and Aceh, which is the least assessed area because of logistical constraints," Egeland told reporters.

"It may therefore raise further," he said.

"We will never ever have the absolute, definite figure because there are many nameless fishmermen and villages that have just gone -- and we have no chance of finding out how many they were," Egeland said.

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