Hurricane Katrina has unleashed howling winds and heavy rain upon southern coastal areas of the United States.
The storm has wrought extensive damage in Mississippi, Alabama and Louisiana, where it swept ashore after moving across the Gulf of Mexico.
Katrina submerged areas of New Orleans and tore off part of the roof of a stadium where many had sought refuge.
But it weakened after making landfall and spared the low-lying city a direct hit, despite frightening predictions.
The hurricane - later downgraded from a category-five hurricane to a category-one storm - still brought 105mph (170km/h) winds to Mississippi.
State Governor Haley Barbour told reporters that Katrina "came in on Mississippi like a ton of bricks".
Correspondents in New Orleans say walls of water have been running down the skyscrapers like waterfalls.
Power lines have been cut, palm trees have been felled, shops wrecked and cars hurled across streets strewn with shattered glass.
Hundreds of thousands have fled, amid fears that the storm surge could topple the barriers that protect the city, which sits some 6ft (2m) below sea level.
Mayor Ray Nagin said he had received reports that some water had breached the defences.
"This city is under siege," he said.
Katrina passed to the east of New Orleans, although the National Hurricane Center warned it would be pounded throughout Monday - and the potential storm surge could still swamp part of the city.
Elsewhere along the Gulf Coast, Katrina flooded roads in Alabama and swamped bridges in Florida.
Pictures from the city of Mobile in Alabama showed water surging through the streets, as the storm spurred a 22-ft (7m) surge on Mississippi's coast.
"This is a devastating hit - we've got boats that have gone into buildings," the Gulfport fire chief said.
State of emergency
President George W Bush called on people who had fled their homes not to return until the authorities told them to.
The president has issued a state of emergency in Louisiana and Mississippi, freeing the path for federal aid.
Three nursing home residents died after being taken by bus to a Baton Rouge church during the Louisiana evacuation.
The storm, which formed in the Bahamas, lashed South Florida on Thursday, killing nine people, uprooting trees, downing power lines and causing extensive flooding.
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