WASHINGTON (AP) -- President Bush on Monday tapped two former presidents -- his father, President George H.W. Bush, and his predecessor, President Clinton -- to lead a nationwide, private fund-raising campaign to help victims of the Asian tsunamis.

"I ask every American to contribute as they are able to do so," Bush said in the White House's Roosevelt Room, the two former presidents at his side.

Clinton and the first President Bush are to lead an effort to encourage the American people and businesses to support relief and reconstruction activities in areas devastated by the tsunamis, the president said. He also ordered that American flags fly at half-staff all week in sympathy for "the victims of a great tragedy," particularly the many thousands of dead and orphaned children.

"In the coming days, Presidents Clinton and Bush will ask Americans to donate directly to reliable charities already providing help to tsunami victims," Bush said. "I've asked the former presidents to solicit contributions both large and small."

The president urged Americans to give money instead of other items. "Cash donations are most useful," he said.

The announcement came as the White House has been scrambling to repair an image battered at home and abroad by perceptions that U.S. aid for the tsunamis lagged behind other countries -- especially considering the outpouring of support for America from other countries in the hours and days immediately following the Sept. 11, 2001, terrorist attacks.

Bush faced criticism for waiting until three days after the Dec. 26 earthquake and tsunami to interrupt his holiday vacation and make his first personal comments about the deadly disaster. Other countries also were quicker to commit large amounts of aid money, and Japan has outpaced the U.S. total of $350 million pledged so far.

But private donations began pouring in from people in the United States and around the world at unprecedented levels almost immediately. Bush's press secretary, Scott McClellan, dismissed any suggestion the White House campaign to encourage private giving was behind that curve as well, saying the new effort was about ensuring that impressive flow continues.

"This will bring even more focus on the need to provide support for these international organizations in the affected areas," he said. "This is a human tragedy that is really beyond comprehension and we want to make sure we're doing everything we can both from the government perspective as well as private support to help those who are suffering."

Bush himself has not yet made a personal contribution, but plans to give an unspecified amount, McClellan said.

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

Later Monday, Bush, accompanied by first lady Laura Bush as well as his father and Clinton, paid brief visits to the embassies of the four nations hit hardest by the disaster -- Indonesia, Sri Lanka, India and Thailand.

At the Indonesian and Indian embassies, Mrs. Bush presented officials with bouquets of white roses and the foursome signed condolence books.

"We look forward to working with the Indonesian government to help those who need food, medicine, water and shelter to get their lives back in order so the great country of Indonesia can rise up from this disaster. May God bless the people of Indonesia," the president said in a brief statement at the Indonesian embassy. He made similar remarks at other embassies.

While at the Indian embassy, Bush said he told the ambassador he intends to travel to India this year. "In the meantime, though, our country stands with the people who have suffered," he said.

The president also was waiting to hear back from a delegation he dispatched to the region to assess what more the United States government can do to help. That team, led by Secretary of State Colin Powell and the president's brother, Florida Gov. Jeb Bush, arrived in the region Monday.

Powell said in Bangkok, Thailand, that the relief effort appears to be going so well that he sees no immediate need for more U.S. governmental money. Coordinating all the international aid is now the most urgent task, he said.

To solicit private contributions, the former presidents will travel the country and do media interviews as part of their effort, McClellan said.

Reflecting the White House's concerns about the damage done, Monday's appearance by Bush was the fifth statement -- either written or verbal -- from the president himself on the disaster in six days. And aides normally tight-lipped about the president's behind-the-scenes activities have been eagerly offering tidbits of Bush's calls to other leaders on the crisis and his monitoring activities.

(Copyright 2005 by The Associated Press. All Rights Reserved.)