NEW ORLEANS – The city of New Orleans imposed a dawn-to-dusk curfew to begin on Sunday at sunset ahead of Hurricane Gustav's devastating winds and rains that were on a path to strike the Gulf Coast.
The Big Easy increasingly took on the eeriness of a ghost town as thousands heeded a mandatory evacuation order, and police and National Guard troops clamped down on the city to prevent the kind of lawlessness and chaos that followed Katrina three years ago.
Painfully aware of the failings that led to that horrific suffering and more than 1,600 deaths, this time, officials moved beyond merely insisting tourists and residents leave south Louisiana. They threatened arrest, loaded thousands onto buses and warned that anyone who remained behind would not be rescued.
In a press conference Mayor Ray Nagin also warned that looting — one of the chronic problems after Hurricane Katrina — would not be tolerated.
"Looters will go directly to jail. You will not get a pass this time," he said. "You will not have a temporary stay in the city. You will go directly to the Big House."
Col. Mike Edmondson, state police commander, said he believed more than 90 percent of the coastal Louisiana population had fled — the largest evacuation in state history.
Nagin has used stark language to get his message across to residents, calling Gustav the "mother of all storms."
"This is the real deal, not a test," Nagin said when he issued the evacuation order Saturday night. "For everyone thinking they can ride this storm out, I have news for you: that will be one of the biggest mistakes you can make in your life."
Emergency officials have repeatedly warned that those who stay are on their own, and there will be no shelter of refuge like in Katrina, when thousands waited helplessly for rescue in a squalid Superdome.
Still, despite the massive evacuations, FOX News learned that several illegal immigrants living in the area were hesitant to leave out of fear that if they got on buses, they would be picked up and deported by Homeland Security.
But an immigration official assured FOX that there would be "no enforcement actions during this time. The Department of Homeland Security just wants people to get out."
Homeland Security Secretary Michael Chertoff, who was headed to the region Sunday, said he planned to stay through the storm.
"I'm well supported in terms of my ability to communicate back to the president and back to Washington, so I'm comfortable that I'm not going to lose touch," Chertoff said.
Gustav crossed western Cuba on Saturday and has already killed at least 94 people in the Caribbean.
Damage from the storm was devastating to Haiti in particular, still reeling from the destruction of Tropical Storm Fay. By week's end, 8,000 people were still in shelters, some running out of food, while a preliminary U.N. report said Gustav's destruction to Haitian cropland was "very significant."
Gustav picked up speed upon reaching the gulf and was moving northwest at 17 mph with winds of 120 mph, according to the National Hurricane Center's 11 a.m. EDT update.
Gustav dropped from a Category 4 to a Category 3 storm overnight, but forecasters warned it could gain strength from the gulf's warm waters before making landfall as early as Monday, and that Gustav could bring a storm surge of up to 20 feet to the coast and rainfall totals of up to 15 inches.
With the storm speeding up and strengthening more quickly than expected on its way across the Caribbean and the Gulf of Mexico, some hospitals changed plans and decided to evacuate patients they had planned to keep on hand, Chertoff said.
"A number of the hospitals that originally planned to shelter in place have now decided they are going to actually try to evacuate their critically ill and medical needs patients," Chertoff told reporters before leaving for Louisiana. "As a consequence, we've had to increase the tempo of our air flights into New Orleans in order to make sure that we can accommodate the flow. We're going to be watching this very carefully today."
In New Orleans, Nagin and other officials took pains to ensure that there would not be a repeat of Katrina, despite the frightening similarities between the two storms.
More than a week ago, at the first hint Gustav could be a threat to New Orleans, police Superintendent Warren Riley issued an unusual order — he gave all the city's 1,485 officers paid time off to get their families to safety.
It was a lesson learned from the bitter experience of Hurricane Katrina, when dozens of officers were roundly criticized for abandoning their posts as their colleagues and the citizens they were sworn to protect were left swamped, scared and at the mercy of lawlessness. Some were called cowards. Several dozen ended up being fired.
Many of the officers who left said the storm forced them to make an agonizing choice: Take care of strangers or take care of your family.
This time around, the department was doing all it could to make sure that officers had enough of a chance to do both, well ahead of Gustav's landfall.
But it was the mandatory evacuation of New Orleans that served as the first true test of the revamped evacuation plan designed to eliminate the chaos, looting and death that followed Katrina.
The city will not offer emergency services to those who choose stay behind, Nagin said, and there will be no "last resort" shelter as there was during Katrina, when thousands suffered inside a squalid Superdome.
For residents with no other means of leaving the city, the last buses were going to leave at 3 p.m. Sunday.
At the city's main transit terminal, a line snaked through the parking lot for more than a mile as residents with no other means of getting out waited to board buses bound for shelters in north Louisiana and beyond.
"I'm not staying for 'em any more," said Lester Harris, a 53-year-old electrician waiting at a bus pickup point in the Lower 9th Ward. He was rescued from his house by boat after Katrina. "I got caught in the water and spent two days on my roof. No food, no water. It was pretty bad."
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Many residents didn't need to be ordered, with an estimated 1 million people fleeing the Gulf Coast on Saturday by bus, train, plane and car. They clogged roadways, emptied gas stations of fuel and jammed phone circuits.
Many residents said the early stage of the evacuation was more orderly than Katrina. Lines for the evacuation buses queuing up at the city's main transit center were much shorter Sunday than they'd been a day earlier.
"I'll be glad when it's over and I hope it doesn't mess up the city too bad," said Johnny Clanton, 59, waiting with a bag, hoping to catch up with a friend who also planned to leave the city.
Click here for a story on evacuations in New Orleans.
FOX News' Catherine Herridge and the Associated Press contributed to this report.