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.
Information for this report is provided by AP, AFP and Reuters.