Across south Asia, the massive effort to get humanitarian aid to the millions of people affected by last week's killer tsunami is having mixed success. In some cases, the aid is already more than enough, while in other countries, relief workers as well as survivors say the devastation in some regions is complicating efforts to reach those in dire need.

For Thailand, it's no longer aid that's needed, but faster ways of distributing it.

"We don't need any financial assistance. We need technical assistance," said Thailand's Prime Minister Thaksin Shinawatra.

With donors from around the world now having pledged more than two billion dollars in aid, the prime minister instead wants more help with the massive job of recovering the dead.

"We still need to search for more corpses which are still missing," he said.

Acehnese youths carry food aid at port in Meulaboh, Aceh province, Indonesia

Indonesia, by far, has been hardest hit, with nearly 100,000 people believed to have perished in the earthquake and tsunami.

"The aid that is coming in is sufficient but the difficulty is to reach all the people because many of them are living in very remote places and distributing aid in remote places where the seashore may have been seriously damaged by the tsunami is going to be a logistical nightmare," said Michael Elmquist, the U.N. relief coordinator in Indonesia.

Correspondents in Indonesia's hardest hit area, the town of Banda Aceh on the Sumatran coast, speak of entire regions where remote villagers - eight days after the earthquake and the wall of water struck - still have not received any aid.

"As we spend more and more time with the families and the victims of this disaster, the scale of the catastrophe at the real personal level is just beginning to become clear," said Nigel Pont of the aid group Mercy Corps.

Much of the devastated area remains off limits to vehicles because of the incredible amount of damage and debris, leaving it up to cargo planes and helicopters to drop aid from the air. Thousands of American Marines and sailors on several warships are either in the region or on the way there.

Sri lankan aid worker prepares to hand out aid at refugee camp set in a school in coastal city of Galle

The situation is similar in Sri Lanka where rescue efforts overland are hindered because of the vast destruction along much of the island's coast.

"The country, the road along the coast from Colombo south all the way around the tip of the island, all the way up to Trincomalee is washed away in many places, a number of bridges are destroyed," said Jeffrey Lunstead, the U.S. ambassador in Sri Lanka. "Those all have to be rebuilt so things can move and people can get back to their livelihood."

George Bush, with former Presidents George H.W. Bush and Bill Clinton

With flags flying at half-mast in Washington in memory of the victims, President Bush Monday enlisted his father, the former President Bush as well as former president Bill Clinton to lead a nationwide drive to raise contributions to private charities involved in the relief effort.

"I ask every American to contribute, as they are able to do so," the president said.

Secretary of State Colin Powell arrived in Bangkok Monday night along with the president's brother, Florida Governor Jeb Bush, to get a first hand assessment of the situation, and to demonstrate the American commitment to the region's recovery.

President Bush had faced criticism for not speaking out immediately after the December 26 disaster and for the initial U.S. aid contribution of just $35 million. That amount has since been increased to $350 million and Congress is expected to approve more in the days ahead.