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So many homeless Louisiana residents were arriving in Houston on Friday that city officials opened two more giant centers to accommodate overflow from the Astrodome (search).

Buses were temporarily turned away from the Astrodome, already packed with more than 15,000 people, because of safety and crowd concerns. The city is expected to receive at least 25,000 people displaced by Hurricane Katrina (search).

Mayor Bill White on Friday said the city's convention center and an exhibition hall at the Reliant Center would accept hurricane refugees, and conventions for the coming weeks would be canceled.

"We see the tragedy which is ongoing in New Orleans, and we are doing the best we can to make sure when people get to Houston they have a decent place to stay," White said.

Evacuees could be in Houston for months at a time, he said, and the city was devising a plan to help people over the long haul.

Despite crowding at the Astrodome, more buses were being loaded Friday at the Superdome in New Orleans, where conditions had become desperate as thousands struggled with lack of supplies, clogged plumbing and no air conditioning.

When the Astrodome filled, Katrina refugees who had finally arrived by bus were left in limbo for more than two hours before they were redirected to the exhibit hall.

The change only added to the frustration of victims like Patricia Profit, who had relatives already inside the stadium.

"Before we left New Orleans, they said everybody will be in the Astrodome," said Profit as she stood outside one of the buses. "'Don't panic, don't worry, you'll still be with your family.' That's what they told us. Now we can't be with our family."

The daylong stream of buses had been halted late Thursday.

"We've actually reached capacity for the safety and comfort of the people inside there," American Red Cross spokeswoman Dana Allen said shortly before midnight. She said people were "packed pretty tight" on the Astrodome floor.

Despite the crowding at the Astrodome, some more buses were being loaded Friday at the Superdome in New Orleans.

Tina Miller, 47, had no shoes and cried with relief and exhaustion as she walked toward a bus Friday. "I never thought I'd make it. Oh, God, I thought I'd die in there. I've never been through anything this awful."

Gov. Rick Perry had announced plans Thursday for Texas to take nearly 75,000 storm refugees. Besides Houston, 25,000 each were to be housed in Dallas at Reunion Arena and in San Antonio at a city-owned complex once home to an Air Force base.

"We will do all we can as a state and a people to help our neighbors to the east who have lost so much," Perry had said in declaring an emergency disaster that freed up money to aid storm victims.

Inside the Astrodome, doctors were having trouble keeping up with everyone needing treatment

"Many people might think there are enough people here, and there are not. We just need help," said Dr. Steven Glorsky, who had treated evacuees for heart attacks, open wounds and diabetes.

"We have a crisis in there."

A few people were arrested in the Astrodome, although Sheriff Tommy Thomas didn't have an exact count. He said some men were arrested for going into the women's showers. Others were arrested for fighting over cots.

Dr. Stuart C. Udofsky, chairman of psychiatry at Baylor College of Medicine in Houston, said about 30 psychiatrists from around Houston are assisting with the mental health needs of those staying inside the Astrodome.

"The Astrodome was designed to have maybe 20,000 people for six hours at the most for something upon which they are all focused," Udofsky said. "To be there 24 hours a day, seven days a week, for an indeterminate period of time, that experiment has never been run -- and we are trying to do that right now."

Thirty-two Red Cross shelters were set up across Texas. Officials in Houston estimated as many as 55,000 people who fled the hurricane were staying in area hotels.