Despite a massive outpouring of donations, emergency aid for the victims of last week's devastating tsunami in the Indian Ocean basin is only just beginning to trickle into some of the hardest hit regions. Although some relief groups expressed frustration with the delays, United Nations officials say they expect to be able to help the vast majority of those affected.

Pledges for tsunami disaster relief efforts topped $2 billion, the U.N. undersecretary general in charge of emergency relief said Saturday. According to Jan Egeland, more than 40 countries have donated funds for short-term recovery efforts and long-term reconstruction. Japan has so far made the largest pledge of $500 million, while the United States has promised $350 million.

But nearly a week after the massive tsunami rolled across the Indian Ocean, Mr. Egeland warned that hunger and disease remain the biggest threat to the survivors. He said emergency relief efforts have been hampered by the destruction of roads, bridges and airports in the affected areas. "We need helicopter carriers. We need ships with helicopters that can be outside of the coasts and not clog further up the airstrips where you see inland. Several countries, including the United States, Australia and India, are already helping in this," he said.

In Indonesia, two American helicopters sent from the aircraft carrier USS Abraham Lincoln landed in Banda Aceh, a provincial capital on Sumatra Island, bringing food and medical supplies to one of the hardest hit areas.

President Bush said they are part of the largest relief effort mounted by the U.S. military in recent times. "More than 20 patrol and cargo aircraft have been made available to assess the disaster and deliver relief supplies - many of those aircraft are already on the scene. We have dispatched the aircraft carrier, Abraham Lincoln, the maritime pre-positioning squadron from Guam and an amphibious ship carrying a Marine Expeditionary Unit. They will soon be in position to support relief efforts, to include the generation of clean water," he said.

In his weekly radio address, the president said Americans stand ready to help. According to Mr. Bush, a U.S. delegation leaves for Southeast Asia Sunday to meet with regional leaders and international organizations to assess what additional aid the United States can provide. "The delegation will be led by Secretary of State Colin Powell and Governor Jeb Bush, who has extensive experience in the state of Florida with relief, rehabilitation and reconstruction efforts following natural disasters," he said.

United Nations officials said the death toll is approaching 150,000 and that an estimated five-million people are homeless from last week's catastrophic tsunami. According to the U.N.'s Jan Egeland, it may be impossible to get a final casualty figure. "I said yesterday that 150,000 would be my estimate. I am sure it will be higher than that. But I'm also sure we will never know how many people were washed to sea and will never ever be found," he said.

Mr. Egeland says Sumatra and Aceh are the hardest hit and up to three-fourths of all casualties may have occurred there.

According to VOA's Nancy-Amelia Collins, who is on the ground in Aceh, a lack of fuel and manpower is hampering relief efforts there. "From what some of the aid workers are saying, you can go up to the airport, and you can see aid just lying in there. They are saying they do not have the trucks, they do not have the petrol for the trucks, they do not have the people to ferry the aid to the refugees. They also say they do not have a clear idea of how many refugees there actually are - not only in Banda Aceh itself - but in the surrounding, outlying areas," she said.

Meanwhile, aftershocks continue to rattle the region with a magnitude 6.5 quake recorded off the coast of Sumatra. The U.S. Pacific Command said the aftershocks have not affected the military's distribution of aid.