Standing in the Roosevelt Room, his father to his right and Clinton to his left, Bush urged all Americans to give generously in response to the disaster.

"Cash contributions are most useful," Bush said, pausing before television cameras to give the Web site for the USA Freedom Corps — www.usafreedomcorps.gov — the government coordinating agency for volunteer efforts and private donations.

"As men and women across the devastated region begin to rebuild, we offer our sustained compassion and our generosity," Bush pledged, "and our assurance that America will be there to help."

Joined by his wife, Laura, and the former presidents, Bush visited the embassies of four tsunami-ravaged countries — Indonesia, India, Sri Lanka and Thailand — and signed condolence books.

Bush was criticized last week for taking three days to interrupt his holiday vacation at his Texas ranch to personally address the human consequences of the most violent earthquake in four decades. On Friday, though, Bush increased the U.S. aid pledge tenfold — to $350 million — and over the weekend he dispatched his brother, the Florida governor, and Powell to the region to ensure that he was getting a firsthand assessment of the damage and needs.

Powell and Jeb Bush, who has had extensive experience overseeing relief efforts in the wake of a series of hurricanes in Florida, were scheduled to go to the Indonesian capital of Jakarta today before visiting flood-ravaged Aceh province Wednesday.

"We pray for victims and families of this epic disaster," Bush wrote in a book of condolence messages at the Sri Lankan Embassy, where Laura Bush brought a bouquet of pale yellow roses. "The American government and American people are dedicated to helping you recover."

At United Nations headquarters in New York, Jan Egeland, the U.N. emergency relief coordinator, praised the effort to rally more private U.S. donations. Private giving will probably match the pledges of nations and organizations, he told a news conference.

Egeland, who had suggested after the tsunami that rich nations were "stingy" in giving to poor ones, said he still wishes the generosity would extend to a score of other forgotten international emergencies.

U.N. officials also worry about the broken promises of past disasters.

Secretary-General Kofi Annan said he doubted governments and other international donors would fully deliver on pledges of more than $2 billion for tsunami victims.

"It is quite likely that by the end of the day we will not receive all of it," he said.