Former presidents George H.W. Bush and Bill Clinton announced a nationwide fundraising campaign Monday to help the victims of Hurricane Katrina, saying they will bring what they learned from reaching out to tsunami victims halfway around the world to a crisis on their doorstep.

"I guess I could say on behalf of all of us that nothing we can do can be an adequate response to the agony we've seen," Clinton said at a news conference at the Reliant Arena. "The reason we decided to do this, not that we think the governments won't do their part, is we need to have a fund where we can fill in the blanks and help people who otherwise will be totally overlooked," he said. "A lot of people, they have no cars, no homes, nothing."

A dozen members of Congress and local and state officials sat on chairs below the podium, among them former first lady Barbara Bush, Sen. Hillary Rodham Clinton (D-N.Y.), Sen. Barack Obama (D-Ill.) and Texas Gov. Rick Perry (R). In the exhibit hall a floor below, more than 4,000 evacuees were waking up on cots to another day of uncertainty in one of Houston's newest shelters.

The Bush-Clinton Katrina Fund will serve as an umbrella for special funds established by the governors of Louisiana, Mississippi and Alabama to assist those displaced in their states and will focus on collecting donations to assist in the long-term recovery plan for areas devastated by the storm, officials said.

The former presidents said they hope to step in where government and relief agencies leave off. "The fund will take the outpouring of generosity to the next level," Bush said.

That outpouring has already been substantial. The Chronicle of Philanthropy reported yesterday that $487 million has been raised in the aftermath of Hurricane Katrina. Corporate donations already were pouring in, including $20 million from Wal-Mart and the Walton Family Foundation, Bush and Clinton said.

With the administration facing public criticism for a slow response to the crisis, there was no sign of friction between the president's father and Clinton. When asked to comment on the criticism of President Bush, his father said: "We can always blame somebody else -- that's one of the things you do after a football game, figure out what went wrong. We're trying to make things better."

Later, on CNN, Clinton said of the hurricane response: "Our government failed those people in the beginning, and I take it now there is no dispute about it. One hundred percent of the people I've talked to here recognize that it was a failure, and I personally believe that there should be a serious analysis of it."

The Red Cross said it has logged 75,000 names on its online registry of hurricane victims staying at shelters in Texas and other states, a database created to help reunite splintered families.

Spokeswoman Tara Lynch also said that the organization has received an unprecedented $404 million in donations as of yesterday morning, much of it from online and telephone donations. She said the agency has opened more than 470 shelters in 12 states and is now helping hurricane victims in 30 states.

Staff writer Marc Kaufman in Washington contributed to this report.