WASHINGTON, Jan 3: US President George W. Bush on Monday nominated two former American presidents, his father George H.W. Bush and Bill Clinton, to lead a nation wide fund-raising effort for victims of the Asian tsunamis.

"I ask every American to contribute as they are able to do so," Mr Bush said in the White House's Roosevelt Room, the two former presidents at his side. After announcing the appointments, Mr Bush visited the embassies of India, Sri Lanka, Thailand and Indonesia to sign condolence books. The two former presidents also accompanied him.

Japan is the biggest donor among 44 countries that have promised aid, pledging $500 million. The US has promised $350 million, Britain $96 million and Sweden $75 million. Canada doubled its aid promise to $80 million on Sunday. China increased its contribution to $60 million, and Taiwan upped its pledge 10-fold to $50 million.

The two former US presidents are to lead an effort to encourage the American people and American businesses to support non-governmental relief and reconstruction efforts, Mr Bush said.

"In the coming days, Presidents Clinton and Bush will ask Americans to donate directly to reliable charities already providing help to tsunami victims," he 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.

Mr Bush faced criticism for being slow to respond to the December 26 disaster. Other countries were quicker to commit large amounts of aid money, and Japan has outpaced the US total of $350 million pledged so far.

But Mr Bush's press secretary, Scott McClellan, dismissed suggestions the president's new move was to improve America's image hurt by the administration's slow response to the disaster.

The move, he said, was to encourage private donations and not aimed at competing with other nations. "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."

Mr Bush himself has not yet made a contribution to the relief effort, but plans to give an unspecified amount, Mr 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.

The ship, currently at sea for a previously scheduled test, is capable of receiving patients by helicopter or by ship. White House officials said Mr Bush was waiting to hear from a delegation he dispatched to the region to assess what more the US government can do to help.

That team, led by Secretary of State Colin Powell and the president's brother, Florida Governor Jeb Bush, arrived in the region on Monday. "As men and women across the devastated region begin to rebuild, we offer our sustained compassion and our generosity and our assurance that America will be there to help," Mr Bush said.

The White House's Freedom Corps outfit, which helps facilitate volunteer efforts around the country, is to assist the two former presidents in soliciting private contributions. The former presidents will travel across the United States and do media interviews as part of their effort, Mr McClellan said.