NEW ORLEANS - Thousands of National Guardsmen with food, water and weapons streamed into Louisiana on Friday to bring relief to New Orleans' suffering multitudes and put down the looting and violence. ''The cavalry is and will continue to arrive,'' said one general.
The assurances came amid blistering criticism from the mayor and others who said the federal government had bungled the relief effort and let people die in the streets for lack of food, water or medicine.
In Washington, President George W. Bush admitted ''the results are not acceptable'' and pledged to bolster the relief efforts with a personal trip to the Gulf Coast on Friday.
''We'll get on top of this situation,'' he said before setting out, ''and we're going to help the people that need help.''
Earlier Friday, an explosion at a chemical depot rocked a wide area of New Orleans and jolted residents awake, lighting up the dark sky and sending a pillar of acrid gray smoke over a ruined city awash in perhaps thousands of corpses, under siege from looters, and seething with anger and resentment.
A second large fire erupted downtown in an old retail building in a dry section of Canal Street.
There were no immediate reports of injuries. But the fires deepened the sense of total collapse in the city since Hurricane Katrina slammed ashore Monday morning.
The blast took place in a section of the city directly across the Mississippi River from the French Quarter. It was about two miles (3.22 kilometers) from the Louisiana Superdome and less than a mile 1 (1.61 kilometers) from the New Orleans Convention Center, the two spots where tens of thousands of hungry, desperate and hostile refugees awaited buses to deliver them from their misery.
Lt. Gen. Steven Blum of the National Guard said 7,000 National Guardsmen arriving in Louisiana on Friday would be dedicated to restoring order in New Orleans. He said half of them had just returned from assignments overseas and are ''highly proficient in the use of lethal force.'' He pledged to ''put down'' the violence ''in a quick and efficient manner.''
''But they are coming here to save Louisiana citizens. The only thing we are attacking is the effects of this hurricane,'' he said. Blum said that a huge airlift of supplies was landing Friday and that it signaled ''the cavalry is and will continue to arrive.''
As he left the White House for his visit to the devastated area, Bush said 600 newly arrived military police officers would be sent to the convention center to secure the site so that food and medicine could get there.
City officials have accused the government _ namely the Federal Emergency Management Agency _ of being slow to recognize the magnitude of the tragedy and slow to send help.
''Get off your asses and let's do something,'' Mayor Ray Nagin told WWL-AM Thursday night in a rambling interview in which he cursed, yelled and ultimately burst into tears. At one point he said: ''Excuse my French _ everybody in America _ but I am pissed.''
Across the city, law and order broke down. Police officers turned in their badges. Rescuers, law officers and helicopter were shot at by storm victims. Fistfights and fires broke out Thursday at the hot and stinking Superdome as thousands of people waited in misery to board buses for the Houston Astrodome. Corpses lay out in the open in wheelchairs and in bedsheets. The looting continued.
Gov. Kathleen Blanco called the looters ''hoodlums'' and issued a warning to lawbreakers: Hundreds of National Guardsmen hardened on the battlefield in Iraq have landed in New Orleans.
''They have M-16s and they're locked and loaded,'' she said. ''These troops know how to shoot and kill, and they are more than willing to do so, and I expect they will.''
At the Superdome, group of refugees broke through a line of heavily armed National Guardsmen in a scramble to get on to the buses. And about 15,000 to 20,000 people who had taken shelter at the convention center grew ever more hostile after waiting for buses for days amid the filth and the dead, including at least seven bodies scattered outside the building.
Police Chief Eddie Compass said there was such a crush around a squad of 88 officers that they retreated when they went in to check out reports of assaults.
''We have individuals who are getting raped, we have individuals who are getting beaten,'' Compass said. ''Tourists are walking in that direction and they are getting preyed upon.''
A military helicopter tried to land at the convention center several times to drop off food and water. But the rushing crowd forced the choppers to back off. Troopers then tossed the supplies to the crowd from 10 feet off the ground and flew away.
''There's a lot of very sick people _ elderly ones, infirm ones _ who can't stand this heat, and there's a lot of children who don't have water and basic necessities to survive on,'' said Daniel Edwards, 47, outside the center. ''We need to eat, or drink water at the very least.''
An old man in a chaise lounge lay dead in a grassy median as hungry babies wailed around him. Around the corner, an elderly woman lay dead in her wheelchair, covered up by a blanket, and another body lay beside her wrapped in a sheet.
''I don't treat my dog like that,'' Edwards said as he pointed at the woman in the wheelchair. ''You can do everything for other countries, but you can't do nothing for your own people.''
Michael Brown, director of the Federal Emergency Management Agency, said FEMA just learned about the situation at the convention center Thursday and quickly scrambled to provide food, water and medical care and remove the corpses.
By midmorning Friday, despite a constant buzzing of military helicopters overhead, there was still no sign of the relief to the tens of thousands lined up outside the convention center.
''I'm trying to keep hope alive, but slowly my hope is fading,'' said refugee Carl Clark. ''Believe it or not, these people are human. Right now they're crowded like animals. They're trying to keep their dignity. ... I don't even know what the Red Cross looks like.''
Raymond Whitfield, 51, watched a National Guard truck drive by the convention center, but like most other official vehicles, it did not stop.
''The National Guard just drives around and around. I know the police, the National Guard, they got generators, so they can sleep and eat,'' he said.
''Look at them,'' he said of the men inside the truck, ''they're not even sweating.''
''Everybody's on the edge right now,'' said 28-year-old Kenya Green. ''Every day, it's 'The bus is coming, The bus is coming,' but still nothing. ... They don't give us no information.''
Conditions were dire at the Superdome as well. By Thursday evening, 11 hours after the military began evacuating the Superdome, the arena held 10,000 more people than it did at dawn. Evacuees from across the city swelled the crowd to about 30,000 because they believed the arena was the best place to get a ride out of town.
The flow of refugees to the Houston Astrodome was temporarily halted overnight after about 11,000 people had arrived _ less than half the estimated 23,000 people expected.
''We've actually reached capacity for the safety and comfort of the people inside there,'' American Red Cross spokeswoman Dana Allen said. She said people were ''packed pretty tight'' on the floor.
Texas Gov. Rick Perry announced that Dallas would host 25,000 more refugees at Reunion Arena and 25,000 others would relocate to a San Antonio warehouse at KellyUSA, a city-owned complex that once was home to an Air Force base. Houston estimated as many as 55,000 people who fled the hurricane were staying in area hotels.
While floodwaters in New Orleans appeared to stabilize, efforts continued to plug three breaches in the levees that protect this bowl-shaped, below-sea-level city, which is wedged between Lake Pontchartrain and the Mississippi River.
Helicopters dropped sandbags into the breach and pilings were being pounded into the mouth of the canal Thursday to close its connection to the lake.
The chief of the Louisiana State Police said he heard of numerous instances of New Orleans police officers _ many of whom from flooded areas _ turning in their badges.
''They indicated that they had lost everything and didn't feel that it was worth them going back to take fire from looters and losing their lives,'' Col. Henry Whitehorn said.
Tourist Debbie Durso of Washington, Michigan, said she asked a police officer for assistance and his response was, '''Go to hell - it's every man for himself.'''
FEMA officials said some operations had to be suspended in areas where gunfire had broken out.
Hospitals struggled to evacuate critically ill patients who were dying for lack of oxygen, insulin or intravenous fluids. But when some hospitals try to airlift patients, Coast Guard Lt. Cmdr. Cheri Ben-Iesan said, ''there are people just taking potshots at police and at helicopters, telling them, 'You better come get my family.'''