Updated

The Bush administration kept its Hurricane Katrina (search) response and its public relations campaign in overdrive on Sunday, even as first confirmation came from Washington of a dreaded statistic — that the storm probably killed thousands of people.

Responding to accusations of racial insensitivity, Secretary of State Condoleezza Rice (search) said, "Nobody, especially the president, would have left people unattended on the basis of race."

Rice, who was sent to her native Alabama, was among four Cabinet secretaries and other high-ranking administration officials who fanned who out across the storm-ravaged region Sunday. President Bush was planning to return to the area Monday, three days after an initial visit, with appearances in Baton Rouge, La., and Poplarville, Miss.

Six days after Katrina lashed much of the Gulf Coast into oblivion, and five days after levee breaks drowned New Orleans and turned it into a place of lawless misery, Homeland Security Secretary Michael Chertoff (search) said military personnel and National Guard troops have secured the city and ensured that those still stranded can be moved out.

But he said significant challenges remain — including how to care for the people being relocated.

"We are still in the middle of the emergency," Chertoff said in a televised interview. "We are moving the city of New Orleans to other parts of the country."

Underscoring the strain of the disaster, Sen. Mary Landrieu, D-La., lashed out at federal officials who she said have denigrated local efforts to deal with the catastrophe.

"If one person criticizes them or says one more thing, including the president of the United States, he will hear from me," she said on the ABC's "This Week." "One more word about it after this show airs and I might likely have to punch him. Literally."

The National Center for Missing & Exploited Children, at the government's request, announced a hot line and Web site dedicated to reuniting family members separated by the storm. By noon EDT Monday, people will be able to get help at 1-888-544-5475 or at www.missingkids.com, where they can post or look through photographs, lists of names and physical descriptions.

There also were warnings of new dangers. Health and Human Services Secretary Michael Leavitt said he had received a report from Biloxi, Miss., of dysentery — a painful, sometimes-fatal intestinal disease that causes dehydration. With hot weather, mosquitos and standing water holding human waste, corpses and other contaminants, diseases such as West Nile virus, hepatitis A, salmonella and E. coli bacteria infections also are a concern, he said in a televised interview.

"We have the ingredients for a bad situation there," Leavitt said.

Hundreds of federal health officers and nearly 100 tons of medical supplies and antibiotics were being delivered to the Gulf Coast to try to head off the problem.

Bush ordered flags flown at half-staff at all public buildings, military facilities, and embassies "as a mark of respect for the victims" until Sept. 20.

Local officials had predicted the death toll would reach into the thousands, and federal officials agreed Sunday.

"I think it's evident it's in the thousands," Leavitt said.

Chertoff said an untold number probably will be found dead in swamped homes, temporary shelters where many went for days without food or clean water, or even in the streets once the water is drained from New Orleans, which could take a month or more.

"I think we need to prepare the country for what's coming," Chertoff said on "Fox News Sunday." "It is going to be about as ugly of a scene as I think you can imagine."

New Orleans Mayor Ray Nagin told NBC News that the situation has been "a tragedy, a disgrace."

The Bush administration continued scrambling to counter criticism that Bush and his administration didn't move aggressively enough right after the hurricane swept through.

The White House quickly arranged another trip by Bush to the Gulf Coast on Monday, while the president and first lady Laura Bush paid a thank-you call on the Red Cross' disaster operations center and announced a White House blood drive.

"The world saw this tidal wave of disaster" hit the Gulf Coast, Bush said at the Red Cross center. "Now they're going to see a tidal wave of compassion."

Besides Rice, Chertoff and Leavitt, Defense Secretary Donald H. Rumsfeld and Joint Chiefs of Staff Chairman Gen. Richard Myers also traveled to the region Sunday.

"It's going to take many, many, many months and into years for this area to recover," said Rumsfeld, who took a helicopter tour of New Orleans, met with military personnel conducting search-and-rescue missions and visited a concourse where evacuated patients were being treated.

Rice — the administration's highest-ranking black — became its chief defender against charges that help, particularly to the disproportionately black and poor victims in New Orleans, came too slowly. "Americans don't want to see Americans suffer," she said in Alabama.

On television, Chertoff was omnipresent, dispatched by the administration to appear on all five Sunday news shows after FEMA Director Michael Brown's damage-control efforts met with little success last week.

Chertoff echoed the White House line — saying the time to place blame will come later, but he also said federal officials had trouble getting information from local officials on what was going on. For instance, he said, they hadn't been told by Thursday of the violence and horrible conditions at the New Orleans convention center.