Authorities are working to evacuate the last hurricane survivors from New Orleans before starting the gruesome task of collecting bodies from the U.S. coastal city.

Officials say 42,000 people were evacuated on Saturday, including everyone who had gathered at New Orleans' football stadium and convention center.

But thousands of people remain trapped in buildings surrounded by floodwaters, six days since the hurricane hit. Meanwhile, corpses have been sighted on porches, sidewalks, and flooded streets, sparking fears of an epidemic.

Some 200 New Orleans police have quit their jobs because of the dire conditions and slow government response to the tragedy.

On Saturday, President Bush acknowledged that many hurricane survivors were not getting the help they need - a situation he called "unacceptable."

The president has dispatched top officials including Defense Secretary Donald Rumsfeld to New Orleans to directly oversee rescue and relief efforts. Mr. Bush will return to New Orleans on Monday - his second visit there in four days.

Officials have said they expect the death toll from Hurricane Katrina to reach the thousands.  Well over 100 deaths have been confirmed in the state of Mississippi, which was also hit hard by Katrina's winds and torrential rain.

Mr. Bush has ordered an additional 7,000 U.S. soldiers to the Gulf Coast states - Louisiana, Mississippi, Alabama and parts of Florida - to deliver relief shipments and massive quantities of construction materials. Another 10,000 National Guards - the armed forces' reserves - have been called to active duty; many of those are assigned to keep public order, especially in parts of New Orleans that descended into anarchy during the frantic first days after the low-lying city was inundated.

Nearly 500,000 people who lost their homes to Hurricane Katrina have been evacuated to Texas, Alabama, Tennessee, Arkansas and other states. The governor of Texas, which has already given refuge to more than 200,000 people from Louisiana, says his state is rapidly approaching the point where it cannot accommodate any more storm victims.

Fleets of buses and airplanes have joined the massive operation in New Orleans, rapidly increasing the pace at which people can be evacuated from the city's two main refuges, the Superdome football stadium and a large convention center. Those buildings remained above the floodwaters last week, but quickly became overwhelmed by a human tide of flood victims, and conditions deteriorated into squalor and violence.

Authorities do not yet know how many people Hurricane Katrina killed. Hundreds are confirmed dead in Mississippi and Louisiana, and the eventual overall death toll is expected to be many times higher.

Some information for this report provided by AFP and Reuters.