City officials said Friday that the death toll from Hurricane Katrina and its aftermath may be far lower than originally feared, as troops and police shifted their attention from rescue of the living to recovery of those who died here in the past 11 days.

The mayor had warned previously that the number of dead in New Orleans could be as many as 10,000, but other city officials said Friday morning that initial sweeps of flooded and devastated neighborhoods suggested a total that would be less cataclysmic, if still tragic.

"Some of the catastrophic deaths some people have predicted may not have occurred," said Col. Terry Ebbert, the city's director of homeland security, declining to provide further details. "The numbers, so far, are relatively minor as compared with the dire predictions of 10,000."

The revised expectations were among the glimmers of hope Friday that pass for good news in the desolate and increasingly empty Crescent City.

Noxious floodwaters continued to recede as more pumps came on line, while power and water pressure were slowly returning to parts of the New Orleans metropolitan area. And two weeks after the first evacuation orders were issued, a steady trickle of departing residents continued to be escorted across the city limits.

Despite earlier threats from Mayor C. Ray Nagin to remove holdouts by force, city officials acknowledged Friday that no one so far had been arrested for a failure to evacuate. Authorities also said they remained hopeful that aggressive persuasion would work on remaining residents, who are being warned that their lives are at risk from toxic floodwaters, scattered fires and other hazards that still menace New Orleans.

"All we can do is plead with them to do the right thing," said Sherry Landry, the New Orleans city attorney. "This city is secure. Their property is going to be okay."

Indeed, more than a week after state and local officials angrily demanded federal assistance, the city is now encircled with military checkpoints and heavily patrolled by about 14,000 National Guard and active-duty troops. Military encampments have sprouted in the Garden District's graceful Audubon Park and other dry locations, while helicopters clatter through the sky and Humvees roar through the streets.

After several days of preparations, the beleaguered Federal Emergency Management Agency and its private contractors began a methodical effort to locate and retrieve corpses and body parts from the floodwaters, trapped inside submerged buildings or tangled in debris. Crews fanned out using flat-bottom boats to deliver corpses into refrigerated trucks parked at the waters' edge.

The bodies are being processed by Kenyon International Emergency Services, a Houston firm with close ties to the Bush administration. Kenyon employees were dressed in white suits, gloves and surgical masks. Company officials have said identification could take weeks in some cases, and next of kin will not be notified until the bodies are turned over to the state of Louisiana.

Reporters were turned away by police in attempts to accompany recovery teams or view them at close range, and authorities said Friday that the restrictions were in place to protect the privacy and dignity of the dead.

FEMA officials came under fire from free-press advocates this week for asking photographers not to take pictures of corpses.

Homeland Security Secretary Michael Chertoff told reporters in Washington that the dead would be recovered "with dignity."

"I want to respect the privacy of victims' families," he said.

Because so many bodies remain unrecovered or unidentified, the official death toll in Louisiana remains at 118. Along the Gulf Coast, a total of 347 deaths so far have been attributed to Katrina.

Elsewhere in the battered region, Lt. Gen. H. Steven Blum, the chief of the National Guard Bureau, toured disaster areas in coastal Mississippi and Louisiana on Friday. As many as 50,000 National Guard troops will remain for as long as four months if necessary, he said.

Because troops probably would spend 30-day tours in the area, as many as 200,000 of the available 319,000 troops currently in the United States could serve in the region by the end of the year, Blum said.

In Houston, doctors announced that they had contained a viral outbreak that caused diarrhea and vomiting for hundreds of Katrina evacuees, according to news reports. About 700 people have been treated, with 40 still in isolation to contain the virus, said Herminia Palacio, director of Harris County Public Health and Environmental Services.

The evacuees had norovirus, which is often seen among cruise-ship passengers. About 3,000 refugees are still in the Astrodome using public restrooms, and cots are lined up in close rows.

Tom Skinner, a spokesman for the Centers for Disease Control and Prevention in Atlanta, said there have been reports of similar illness at Katrina shelters around the country but it does not appear to be a widespread problem.

"We're getting reports of clusters of cases of diarrheal illness," Skinner said. "In these shelters, it's important for the medical professionals to pay close attention to hygiene."

Across Lake Pontchartrain from New Orleans, residents of St. Tammany Parish were allowed to return to their homes to survey damage and begin cleanup. Postal offices reopened in many areas south of New Orleans, though flooding made deliveries impossible.

Officials also said the number of customers without power in Louisiana had dropped to 350,000 and that more were coming back on line by the hour. But it could be months before some of the hardest-hit areas, including the Ninth Ward and St. Bernard's Parish, have electricity again, according to an Entergy executive.

New Orleans Police Superintendent P. Edwin Compass III told reporters that the department so far has accounted for only about 1,200 of its 1,730 officers. Officials said previously that many officers abandoned their posts in the chaotic days after Katrina struck, while an unknown number may have been killed.

And even as the search for the dead intensified, some troops and police continued efforts to persuade remaining residents to leave. Near the convention center, doctors and other medical personnel are screening residents on their way out of town.

Anthony Robert Nobles, 38, who was waiting under a medical tent for a bus ride, said he had enough food and water to survive in his Center City apartment building, where a group of about a half-dozen friends helped one another.

But Nobles said he finally decided to leave after repeated visits from troops, who warned him about the hazardous water and scrawled the number "5" on his building, indicating the number of people alive inside.

"Nobody wants to up and leave their home," Nobles said. "But today was the day I could feel it. . . . I didn't think it would get any worse, but they said it's going to get much worse."

Another resident, Christopher Andrew, was helped off a military truck in the same area by paratroopers from the 82nd Airborne Division. He was carrying a covered casserole dish of his homemade vegetable stew.

Unlike Nobles, Andrew was not happy about leaving. "I was forced out," he said. "They said we had to come."

Eggen reported from Washington. Staff writer Josh White in New Orleans contributed to this report.

As soldiers with the 82nd Airborne patrol the streets, crews have begun retrieving corpses and delivering them to refrigerated trucks.Phil Fricano reunites with his dog Pretty Face, who was rescued by an airboat crew. Other residents of the city are slowly regaining electricity and have returned to begin cleanup.