President Bush yesterday sought $10.5 billion from Congress as a first installment to fund the response to Hurricane Katrina and, in a rare request for individual sacrifice, asked Americans not to buy as much gasoline to address oil shortages caused by the storm.

As the crisis in New Orleans and along the Gulf Coast deepened, Bush moved on several fronts to address the economic, humanitarian and security consequences while defending his administration against complaints that it was slow to react to the catastrophe. Bush spent much of the day meeting with advisers, talking with lawmakers and consulting with economists, and he plans to fly to the region today to inspect the damage.

"We all know this is an agonizing time for the people of the Gulf Coast," the president said in an Oval Office appearance with his father, former president George H.W. Bush, and his predecessor, Bill Clinton, who will lead disaster fundraising efforts as they did after last winter's Asian tsunami. "I ask their continued patience as recovery operations unfold. I can assure them that the thoughts and prayers of the entire nation are with them."

With the Gulf of Mexico oil industry effectively shuttered and gasoline prices rising to unprecedented heights, Bush seemed particularly focused on the potential for nationwide economic instability. With little notice, he summoned Federal Reserve Chairman Alan Greenspan to have lunch with him at the White House.

Putting an optimistic face on the situation, Bush tried to reassure the nation. "In our judgment, we view this storm as a temporary disruption that is being addressed by the government and by the private sector," he said.

But he cautioned that "it's going to be hard to get gasoline to some markets" and asked the public to conserve. "Americans should be prudent in their use of energy during the course of the next few weeks," Bush said. "Don't buy gas if you don't need it."

The president also solicited charitable contributions, and the White House said he and first lady Laura Bush were sending a personal donation to the Red Cross, although it would not divulge the amount.

The supplemental appropriation Bush is seeking from Congress will direct $10 billion to the Federal Emergency Management Agency for relief efforts over the next few weeks and an additional $500 million to the Defense Department to defray its own expenses in reacting to the storm's devastation. Bush spoke with legislative leaders from both parties and Congress, which was on recess until after Labor Day but decided to return early to consider the spending package. The Senate rushed back last night and promptly approved the request, and the House plans to reconvene today.

Bush aides said the appropriation request would be only a small fraction of the cost of recovery and reconstruction to deal with the hurricane, which cut a swath of damage across Louisiana, Mississippi and Alabama. "The $10.5 billion is, indeed, a stopgap measure," said Joshua B. Bolten, director of the Office of Management and Budget. "We do not have a good sense . . . of how much the recovery from this disaster is likely, ultimately, to cost."

The extent of the damage led Bush to waive the local and state share of response costs for the next 60 days, meaning that the federal government will absorb 100 percent of the expense rather than 75 percent. The president said the destruction eclipsed even the terrorist attacks of Sept. 11, 2001.

"New Orleans is more devastated than New York was and just physically devastated, as is the coast of Mississippi," Bush said in an unusual appearance on ABC's "Good Morning America." But he vowed to rebuild New Orleans "as a great city" again.

That commitment may face some second-guessing. In an interview published yesterday, House Speaker J. Dennis Hastert (R-Ill.) questioned whether it was a wise use of federal funds to rebuild a city situated below sea level in a hurricane zone. "It doesn't make sense to me," he told the Daily Herald of Arlington Heights, Ill. "And it's a question that certainly we should ask."

Bush, who will travel to New Orleans, Mobile, Ala., and Biloxi, Miss., today, employed a personal touch in reaching out to the afflicted areas, at one point calling a Coast Guard petty officer involved in rescue efforts. He expressed empathy for residents aggravated by what they see as a slow, ineffective federal response. "I fully understand people wanting things to have happened yesterday," he said on ABC. "I mean I understand the anxiety of people on the ground. . . . But I want people to know that there is a lot of help coming."

At the same time, Bush took a stern tone about looters. "There ought to be zero tolerance of people breaking the law during an emergency such as this, whether it be looting or price gouging at the gasoline pump or taking advantage of charitable giving or insurance fraud," he said.

Asked later whether that included those stealing food or water to survive, White House press secretary Scott McClellan said yes. "There are ways for them to get that help," he said. "Looting is not the way for them to do it."

President Bush: "We all know this is an agonizing time."