Workers broke ground Wednesday for four refugee camps on the devastated island of Sumatra, where an estimated 1 million are homeless from last week's deadly tsunami (search), and pledges of aid — led by a new donation from Australia — neared $4 billion.

On the eve of a summit to discuss how to distribute aid for victims of the Dec. 26 earthquake and Indian Ocean tsunami, Australia announced a package of $810 million in grants and loans, making it the No. 1 single donor. Earlier in the day, Germany increased its pledge to $674 million, surpassing commitments by Japan of $500 million and the United States of $350 million.

Secretary of State Colin Powell (search), one of the first world leaders arriving for Thursday's summit, toured the hardest-hit areas along Sumatra's flattened coast and the former general described the wreckage as worse than a war zone.

"I cannot begin to imagine the horror that went through the families and all of the people who heard this noise and then had their lives snuffed out by this wave," Powell said after flying over the site.

"I've been in war and I've been through a number of hurricanes, tornados and other relief operations, but I've never seen anything like this."

Across Europe at noon Wednesday (6 a.m. EST), politicians, workers and tourists observed a three-minute silent tribute for the victims across southern Asia. TV and radio stations interrupted programming and church bells rang.

The four new camps being built around Banda Aceh (search), the main city in northern Sumatra, are sorely needed, as the existing ones are overcrowded and lack proper facilities.

"The camps that are here have been improvised by the people themselves," said Michael Elmquist, who heads the U.N. relief effort in Aceh. "But these are definitely not according to our standards. The sanitation is totally insufficient."

Elmquist said the United Nations will provide tents and equipment for up to 500,000 people.

Along with Powell, the donor conference is expected to draw U.N. Secretary-General Kofi Annan (search), Australian Prime Minister John Howard (search), Chinese Prime Minister Wen Jiabao (search) and Japanese Prime Minister Junichiro Koizumi (search).

There have been nearly 150,000 confirmed deaths from the 9.0 magnitude earthquake that rattled the ocean floor and sent massive waves crashing across beachfront communities from southern Asia to Africa. The toll is expected to climb above 150,000.

In announcing the largest single pledge, the Australian prime minister said his country's aid will help Indonesia rebuild.

"This is a historic step in Indonesian-Australian relations in the wake of this terrible natural disaster," Howard said in Jakarta.

Half of the money will be in grants for short-term relief and the remainder in loans for long-term reconstruction.

It was not immediately clear if the new pledge was in addition to Australia's existing gift of $47 million to the relief operations.

German Chancellor Gerhard Schroeder said his country's pledge of $674 million would be made available over a minimum of three and a maximum of five years. At least 60 Germans died in the disaster — the highest official death toll for foreigners to date.

"The whole German nation has solidarity with the people of the region and we are all proud ... of the German people's readiness to help," Schroeder said.

The aim of Thursday's meeting is to get donors to commit to specific aid and reconstruction projects, said Bo Asplund, U.N. representative in Indonesia.

Topping the list of demands is Indonesia, Asplund said, with some $450 million required under a U.N. appeal for the country that suffered at least 94,200 deaths.

Bringing together representatives of all the affected countries will allow aid officials to get commitments for relief for at least the next six months, Elmquist said. The countries also hope to prevent future disasters by creating a tsunami warning system for the Indian Ocean.

Another issue will be possible debt relief to affected countries, many of which are developing nations that rely on international assistance. Britain's top treasury official has said the world's richest nations are likely to freeze debt repayments and may even forgive debts to countries hit by the tsunami.

Marine helicopters Wednesday buzzed into Medan, Indonesia, not to bring food in, but to take supplies away. Aid has flooded into Medan and the supplies were stacked in disorganized piles near a warehouse at the city's airport, an overwhelming amount beyond what was immediately needed in the area.

Desperate to get the supplies to hard-to-reach areas on Sumatra's west coast, CH-46 helicopters from the USS Bonhomme Richard launched an airlift Wednesday to bring the aid back to their ship.

The fragility of relief efforts was underscored by the temporary closure Tuesday of the main, overstretched airport in Sumatra. On Wednesday, a load of aid supplies fell from a U.S. helicopter over the island's city of Medan, hitting a shopping mall. No one was hurt.

Survivors expressed gratitude to the United States for the aid, saying it could help America's tattered image in the Muslim world.

"America is the police of the world. But at the same time, they are helping us," said Mohamed Bachid Madjid, standing on a bridge over the Aceh River, where two corpses floated amid the rubble. "And we are grateful."

With hospitals overcrowded, about a dozen people lay on stretchers on the sidewalk outside Fakina Hospital in Banda Aceh. Many of the hospital's rooms had no power. Walls were flecked with blood and doctors had run out of stands for intravenous fluid bags, hanging them from cords strung across the ceiling.

Hospital workers said many people had infected wounds, some of which were turning gangrenous, forcing surgeons to amputate limbs.

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

In Thailand, where more than 2,200 foreign tourists were among 5,000 killed, police said they were searching for a 12-year-old Swedish boy last seen leaving a hospital with an unknown man the day after the tsunami hit. Authorities said they could not confirm news reports that Kristian Walker had been kidnapped; a German sought in the boy's disappearance turned himself in and has been cleared, police said Wednesday.

Police and U.N. officials have expressed fears that trafficking gangs will exploit the chaos of the disaster to abduct children and sell them into forced labor or even sexual slavery.

UNICEF director Carol Bellamy and World Health Organization Director-General Dr. Lee Jong-wook toured Banda Aceh on Wednesday, visiting hospitals and makeshift clinics tending the thousands of injured.

In hard-hit southern India, a team of psychiatrists is visiting refugee camps to treat those like 28-year-old Meenakshi, whose four children between the ages of 4 and 12 were swept away by a wall of water in the fishing village of Nagapattinam. While other survivors clamored for rice, the guilt-ridden woman, who like most south Indians uses only one name, sat in the corner and stared vacantly at the walls.

"Why didn't God spare me even one?" she asked repeatedly.

"She barely talks, just lies there blaming herself," says her husband, Kailasam, a 32-year-old fisherman who was away at sea when the tsunami struck.

"For days she wandered about like someone gone mad, climbing over mounds of debris, searching and calling out to the children. ... Now she just sits. Or weeps."

In Thailand, rescue workers freed a humpback dolphin from a small lagoon where the tsunami dumped it, returning it to the Andaman Sea.

The dolphin, spotted Monday about a half-mile from the beach by a man searching for his missing wife, had become a symbol of hope amid the death and destruction.