The US military on Wednesday added Navy ships, including two helicopter assault vessels and the hospital ship Comfort, and dozens of helicopters to a massive relief effort in the wake of killer Hurricane Katrina.
Officials in New Orleans were pressing the military to help evacuate the flooded city and the Superdome stadium, where thousands of refugees were gathered. Pentagon spokesman Bryan Whitman said that "there's an option there to use military resources" in the evacuation but no decision had been made.
Whitman said 48 Army helicopters were prepared to leave Fort Hood, Texas, to take part in the relief effort. They would join more than 30 Army, Navy and Marine Corps helicopters already working the devastated coasts of Louisiana and Mississippi.
No immediate order was given to commit active-duty federal troops to the area where Katrina slammed ashore on Monday, but Whitman said some 8,500 part-time National Guard soldiers and airmen had been mobilised for duties from law enforcement to providing water and power generators.
Those Guard members included 1,007 sent by Texas and small numbers contributed from Colorado, Pennsylvania and Oklahoma, Whitman said.
The military's Northern Command said the Navy hospital ship Comfort, with 12 operating rooms and 1,000 beds, would soon depart Baltimore for a weeklong trip to the area, and the helicopter carrier USS Bataan and another warship were already conducting rescue missions from off the Louisiana and Mississippi coasts.
The USS Iwo Jima, another helicopter assault ship, was also preparing to sail from Norfolk, Virginia, with three other vessels and was due to arrive in five days, the Navy said.
The Bataan and the Iowa Jima carry heavy MH-53 and HH-60 medical evacuation and supply helicopters.
"This is a developing situation and we are going to make sure that the department provides the necessary help," Whitman told a Pentagon briefing on the military response to one of the worst natural disasters ever to hit the United States.
The military set up a task force at Camp Shelby, Mississippi to co-ordinate support for the disaster-relief effort led by the Federal Emergency Management Agency.
The moves came as the Army Corps of Engineers in New Orleans planned to help the National Guard drop 3,000-pound (1360 kg) sandbags into an opening of a protective levee that has caused the flooding of most of the tourist area two days after Katrina ripped ashore.
Initial attempts failed plug a 200-foot (60-metre) gap in the levee system with the sandbags and concrete barriers, but officials said they would keep trying.
The Northern Command, which is co-ordinating help to FEMA, said that the first of eight military "swift water" rescue boats and elite civilian crews were flown in from California overnight.
Active-duty troops cannot take part in police duties within the United States, unlike the National Guard and Coast Guard, the Northern Command said. "Typical defence support of civil authorities in disasters includes logistics, communications and medical care," it said.
In New Orleans, the Corps of Engineers said it could begin on Wednesday to help drop the giant sandbags into an opening of the 17th Street Canal floodwall from twin-rotor helicopters to try to fill the breach.
Guard officials said that after the breaks in the floodwall were repaired, the corps planned to break an opening in a lower portion of another levee around New Orleans so trapped water could begin flowing out of the city.