Milvertha Hendricks, 84,  waits in the rain with other flood victims outside New Orleans convention center

Desperation is turning to anger in New Orleans as tens of thousands of people left homeless by flooding from hurricane Katrina wait for rescue and relief teams to reach them. Help is on the way, but many people think it is coming far too slowly.

Widespread looting and other criminal acts continued during the fifth day of New Orleans' crisis, and police and emergency workers were forced to take cover from repeated gunfire. Fiery explosions ripped through the city's waterfront before dawn Friday, but police said they were unable to leave the protection of their stations to investigate.

Meanwhile, helicopters are ferrying people out of New Orleans and bringing in medicine, food and water. The most massive effort is focused on the Superdome, where more than 20,000 people took shelter last weekend as Hurricane Katrina approached. They have been trapped there all week in a hot, wet and increasingly dismal situation.

Chief of National Guard operations Lt. Colonel Pete Schneider says bus convoys are taking people to Houston, where they will be provided shelter in that city's Astrodome stadium, but he says it is difficult to keep track of the numbers.

"Some have started to arrive in Houston. Another thing is that we have had is that we have had people join into those convoys to arrive in Houston who did not start at the Superdome. So we are getting people added into the convoy as we go along," he explained. "So, as you can imagine, giving you accurate numbers although we are attempting to give you as accurate a figure as we can, giving you the precise number of people is rather difficult at this time."

But many local residents and even some public officials are expressing frustration over what they see as the snail's pace of rescue operations. U.S. Congressman Charlie Melancon, who represents the hard-hit district in the southeastern part of the New Orleans metropolitan area, says he expected the federal government to come in faster with all the resources needed.

"I just cannot believe that we can go and set up as quickly as we did in Iraq, with communications systems, et cetera, and we cannot get that down in New Orleans," he said.

In his visits to the devastated areas, the congressman says he encountered the grim reality of people left stranded for days in a state of shock, in some cases literally staring death in the face.

"They are telling me that they are tying bodies together so that they do not drift away. I was told that a little infant baby that was newborn died in the refugee camp," he said. " When we asked if they needed body bags for the people that they had in St. Bernard, they said, 'Yeah, bring us over a hundred for starters'. They are dying there at the port, just trying to get out."

Military helicopter makes food and water drop to flood victims near Convention Center in New Orleans, Thursday

Journalists and other observers in the flooded city tell similar stories. They say thousands of people in the city's convention center have been left with no food, water, medicine or sanitation. Federal officials say they did not know about that situation until Thursday and are now taking steps to aid those people.

But there were other scenes that clearly showed a lack of logistical coordination. Hospital workers took their most critical patients to the roof of their building to await helicopters that failed to arrive. Some of the patients worsened in the hot sun, and a few died. People stranded in the city also complain about a lack of security. Police have been outnumbered and outgunned by gangs of delinquents with assault rifles who have looted stores, stolen rescue vehicles and even fired shots at boats and helicopters involved in the relief effort.

Late Thursday, 300 National Guard soldiers from Arkansas arrived in Louisiana to take up positions in New Orleans. They are armed with automatic weapons and are ready to respond to attackers. There are already several thousand troops in the city and federal officials say the number will grow by 1400 a day over the next few days.