Updated

President Bush is tapping his father, the former President George H.W. Bush (search), and former President Clinton (search) to spearhead a fund-raising effort among Americans to contribute aid to victims of the Asian earthquake and tsunami disaster.

American businesses and the public will be encouraged to support the victims through private contributions to nongovernmental organizations, the president said.

"We have come together to express our sympathy for a great tragedy," Bush said in an announcement at the Roosevelt Room. "We mourn especially the tens of thousands of children who are lost. We think about the tens of thousands more who will grow up without their parents or brothers or sisters."

Bush said the U.S. military has taken the lead in surveying the damage and distributing supplies. C-130 planes have handed out supplies. The USS Abraham Lincoln (search) has already been dispatched to provide supplies via helicopter and distribute fresh drinking water, he said.

"We're showing the compassion of our nation in our swift response, but the greatest source of America's generosity is not our government, it's the good heart of the American people," Bush said, listing a litany of private organizations — including the Red Cross, the Salvation Army, America Cares, Catholic Charities and Save the Children — that have received contributions and responded immediately

"To draw even greater amounts of private donations, I have asked two of America's most distinguished private citizens to head a nationwide charitable fund-raising effort. Both men, both presidents, know the great decency of our people. They bring tremendous leadership experience to this role and they bring good hearts. I am grateful to the former presidents, Clinton and Bush, for taking on this important responsibility and for serving our country once again," Bush said.

Americans have shown an outpouring of sympathy for the victims of the tsunami waves that struck in the Indian Ocean on Dec. 26 and left 137,000 dead and another 5 million homeless. So far, international government efforts have raised $2 billion toward relief and most experts expect U.S. private contributions to surpass the U.S. government's response.

The United States has contributed $350 million toward the relief effort so far, of which $37 million is already available on the ground in the region. The United States is leading a coalition of nations that include Australia, Japan and Canada in coordinating relief.

Bush said people can go to the USA Freedom Corps (search) Web site to make contributions and find out how they can help.

The former presidents will travel the country and do media interviews as part of their effort, focused on American giving, Bush said.

After the announcement, Bush and the former presidents visited four embassies of nations struck by the tsunamis — Indonesia, Sri Lanka, India and Thailand — to sign condolence books. White House Press Secretary Scott McClellan added the president intends to make a personal contribution to the relief effort.

At the Indonesian embassy, Bush said he looked "forward to working with the Indonesian government to help those who need food and medicine and water and shelter, to get their lives back in order so that the great country of Indonesia can rise up from this disaster and provide the hope necessary for the people of that important country."

At the Indian embassy, he thanked that country for taking a lead in recovery efforts and added that he planned to travel to that country this year.

As the president announced his predecessors' efforts, Secretary of State Colin Powell and Florida Gov. Jeb Bush, the president's brother, arrived Monday in the region to survey the damage and report back on what needs are most imminent. They are visiting Thailand, Indonesia and possibly Sri Lanka.

On the way to Bangkok, Thailand, en route to his destination, Powell said that he didn't expect the U.S. government would be contributing more money right away.

"At the moment, I don't see a need for any additional financial added to the number but President Bush has made it clear that we will do what is necessary," he said.

At the same time, U.S. Marines landed near the Indonesian island of Sumatra, which is ground zero for the tsunamis that were triggered by a 9.0-magnitude earthquake off the island's coast. They are traveling across the Indian Ocean to deliver food aid and supplies to the ravaged nations.

The Pentagon also sent out the USNS Mercy (search), a 1,000-bed hospital ship, to join the tsunami relief effort in south Asia, two officials said Monday, speaking on condition of anonymity. The ship, based in San Diego but currently at sea for a previously scheduled test, is capable of receiving patients by helicopter or by ship, either at anchor or while underway.

FOX News' Trish Turner and Sharon Kehnemui Liss and The Associated Press contributed to this report.