Haggard, dehydrated survivors of Asia's tsunami (search) catastrophe are flooding hospitals in the disaster zone, posing a new challenge for the global relief operation.

As U.S. Secretary of State Colin Powell (search) and other American officials toured the region, the fragility of the aid network was exposed when a cargo plane hit a herd of cows on an Indonesian runway, temporarily shutting down an airport vital to efforts to help.

Another gripping survival tale emerged from the Dec. 26 disaster that killed an estimated 150,000 people and left 5 million in need. Officials said an Indonesian man swept out to sea was found alive, afloat on tree branches and debris about 60 kilometers (100 miles) from shore.

Survivors, however, faced a newly emerging aid bottleneck on Tuesday as a growing helicopter fleet ferried the injured and sick from ravaged villages to overcrowded, undersupplied city hospitals.

A dozen people lay on stretchers on the sidewalk outside Fakina Hospital in Banda Aceh (search), provincial capital of Indonesia's Aceh province on hard-hit Sumatra island. Many of the hospital's rooms had no power. Walls were speckled with blood and doctors had run out of stands for intravenous fluid bags, hanging them instead from cords strung across the ceiling.

"It's heartbreaking," said Leslie Ansag of Everett, Washington, a Navy medic from the USS Abraham Lincoln, an aircraft carrier off Sumatra to help the rescue effort.

The focus on aid needs intensified as world leaders headed to southern Asia to get a close look at the damage and work out a relief plan at a donor conference Thursday in Indonesia's capital, Jakarta.

Powell, who visited Thailand and Indonesia on Tuesday, pledged America's full support. The United States "will certainly not turn away from those in desperate need," he said.

He said the outpouring of U.S. aid and humanitarian help — the government has pledged $350 million (264 million euro) and citizens are donating tens of millions more — could help Muslims see the United States in a better light.

"What it does in the Muslim world, the rest of the world, is giving an opportunity to see American generosity, American values in action," said Powell, who is accompanied by Florida Governor Jeb Bush, a brother of President George W. Bush.

Japan, which has pledged $500 million (377 million euro) to aid efforts, and is preparing to dispatch soldiers and aircraft to the disaster zone, sent a 20-member military team Tuesday to study the region's needs.

Banda Aceh's main airport was closed for most of the day after a Boeing 737 relief plane hit cows on the runway. The closure stopped planes from using the airfield until the craft could be dragged away.

Thursday's aid conference in Jakarta and a subsequent disaster meeting in Kobe, Japan, are to focus on southern Asia's need for a sensor system to issue early tsunami warnings.

Experts say such a system would have cut casualties substantially, and the Thai government on Tuesday removed the head of its meteorological department, Suparerk Thantiratanawong, for failing to warn the nation of the impending disaster. More than 5,000 people were killed when waves slammed into Thai coastal communities.

"If he warned, the death toll would definitely have been minimized," said Prime Minister Thaksin Shinawatra.

Suparerk was assigned to work for six months to help develop a warning system similar to one the Japanese government uses to issue tsunami alerts within minutes of underwater earthquakes. Thai officials said they hoped for technical aid from Washington.

Despite the bottlenecks at hospitals, helicopters from the U.S. military and other nations continued to fly into devastated parts of Sumatra.

Pilot Lt. Ruben Ramos of San Juan, Puerto Rico, found a village where dozens of villagers bounded out of the forest for aid packages. Almost all ran forward, thrusting out their hands and then pressing them to their hearts in a gesture of thanks.

Despite the awesome power of the waves, survivors continued to turn up — even at sea.

Rizal Sapura, 23, was rescued by a Malaysian cargo ship in the Indian Ocean about 60 kilometers (100 miles) off Aceh province, said Adrian Arukiasamy, a spokesman for shipping company K-Line Maritime Malaysia Sdn. Bhd.

Crewmen on the container ship returning to Malaysia from South Africa spotted him Monday evening clinging to the branches of a floating tree, Arukiasamy said.

"It was certainly a miraculous survival," he said.