The U.S. military probably will double the number of helicopters assigned to south Asia tsunami (search) relief missions and is prepared to send several portable hospitals and other additional medical help, senior U.S. military and civilian officials said Tuesday.

Adm. Thomas Fargo, commander of Hawaii-based Pacific Command, told a Pentagon news conference that about 45 U.S. helicopters are now involved in the relief mission, dubbed Operation United Assistance (search). That number probably will double, although the exact number will be determined in part by the amount of additional aircraft provided by other responding nations, he said.

In all, about 13,000 U.S. military personnel are involved in the relief effort, including about 11,600 aboard ships and about 1,000 in Thailand (search), where an air base is serving as the U.S. command center. There also are U.S. military personnel in Sri Lanka, Indonesia and Malaysia.

In a separate news conference, William Winkenwerder, the assistant secretary of defense for health affairs, said the military is prepared to send as many as eight portable hospitals, including a 25-bed version that could be flown aboard two C-17 cargo planes from Yokota air base in Japan.

The military also is prepared to send mortuary affairs groups to help deal with recovered human remains, he said.

The White House, meanwhile, said President Bush ordered that $65 million of "defense articles and services" be drawn from Pentagon inventories to provide disaster assistance to Indonesia, Thailand, Sri Lanka, India, Maldives, Malaysia, Burma, Kenya, Somalia, Tanzania, Bangladesh and the Seychelles.

Two 10-person teams of military and civilian forensics specialists have already been sent from the Joint POW/MIA Accounting Command in Hawaii to assist in recovering, sorting and identification of remains. Winkenwerder said about another 100 forensics specialists would be sent.

Winkenwerder said the Defense Department was coordinating with other government agencies and with the United Nations and World Health Organization to determine what additional medical assistance is needed. He cited the vulnerability of the hundreds of thousands of displaced people in Indonesia and other countries hit by the earthquake and resulting tsunami on Dec. 26.

"All of this creates a breeding ground for disease and for epidemics, and we're concerned about the possibility of that," he said. Cholera, hepatitis-A and other waterborne infection diseases are threats, he said, as are measles and malaria.

Fargo said helicopters, capable of flying from aboard ships or from land bases and able to operate around the clock from austere landing strips, are especially useful in relief operations.

"Helicopters are a tremendous advantage, because, of course, they don't have the same restrictions as fixed-wing aircraft in terms of how many you can have on the ground at a time," he said.

There are 17 helicopters aboard the aircraft carrier USS Abraham Lincoln, which is operating off the coast of Sumatra, which suffered some of the heaviest damage, and there are 25 aboard the USS Bonhomme Richard, an amphibious assault ship that began flight operations off Sumatra on Tuesday.

There also are four land-based U.S. helicopters operating in the area, and Fargo said the USS Fort McHenry is headed to the area from Okinawa with six CH-46 medium-lift helicopters.

A combat supply ship, the USNS Niagara Falls is also headed to the area from Guam with additional helicopters, Fargo said, adding that the government of Singapore plans to send additional helicopters.

Fargo said he had no estimate of how much the military portion of the U.S. disaster relief effort is costing, but he noted that it costs about $2.5 million a day to operating a carrier strike group like the one headed by the USS Abraham Lincoln off the coast of Sumatra.

Fargo said preparations are underway to deploy the USNC Mercy, a 1,000-bed hospital ship based at San Diego. He said a final decision on its readiness has not been made, but it has been on sea trials this week "to make sure that she's ready to go." Other defense officials said the Mercy has been loading and taking on fuel in preparation to leave before the end of the week.

Officials are working on an "imaginative way" to deploy the Mercy, Fargo said.

"You know that these hospital ships were normally used for trauma in combat, but we think that there may be an opportunity to configure the Mercy with a humanitarian assistance crew that might be staffed significantly by nongovernmental organizations and people that have significant medical capability and can provide relief in other forms," the admiral said.