The Bush administration said Wednesday it will be taking its response to the Asian tsunami disaster to "a new level" amid fears the death toll in countries around the Indian Ocean could exceed 100,000. President Bush said India, Australia and Japan are joining the United States in a coalition to respond to the daunting relief needs.

The intensified U.S. response was led by President Bush, who telephoned the leaders of countries hardest hit by the disaster and announced formation of the four-nation "core group" to coordinate worldwide assistance efforts.

Mr. Bush, who had come under media criticism for not speaking publicly on last Sunday's earthquake and tsunami, met reporters in Crawford, Texas, and pledged a multi-faceted U.S. response going far beyond the $35 million in aid initially pledged:

"These few days have brought loss and grief to the world that is beyond our comprehension,” said Mr. Bush.  “The United States will continue to stand with the affected governments as they care for the victims. We will stand with them as they to rebuild their communities."

At a news conference, U.S. Marine Corps Lieutenant General James Conway, Operations Staff Director of the military Joint Chiefs of Staff, said the Pentagon will divert more than a dozen Navy ships to the region.

Several of them are carrying helicopters to assist in rescue and relief operations. Others have the capacity to produce large quantities of clean water, a critical need in stricken areas where concern is mounting about the spread of disease where local water supplies are contaminated.

Appearing with General Conway, Andrew Natsios, administrator of the U.S. Agency for International Development (USAID), said he feared that the death toll from the disaster could exceed 100,000.

He said officials of the U.S. aid agency have begun to assess damage in more remote areas of the affected region, including Indonesia's war-torn Aceh province, and report that death rates "exceed anything" the media have reported thus far.

"There are areas of Aceh that have not been accessible to anybody, including the national government of Indonesia,” he said.  “And they only today approved, in Indonesia, access by the international community to the area. I think we have a sort of cease-fire in place, according to our friends in Indonesia, that will allow us access. But the deaths in Indonesia are much larger than anybody, including the Indonesian national government realize."

Mr. Natsios appealed to concerned private Americans to make cash contributions to relief agencies working in the stricken areas, rather than giving material goods, like clothing and food, which will be prohibitively expensive to deliver to the region.

The agency chief estimated governmental contributions thus far to be about $110 million, but that the process of assessing needs had only begun.

Secretary of State Colin Powell, who Wednesday telephoned U.N. Secretary-General Kofi Annan and the leaders of the other countries in the disaster response "core group" says eventual world-wide contributions will be in the billions of dollars.

Only 12 Americans are confirmed dead from Sunday's calamity but between 2000-3000 U.S. citizens are unaccounted for.

State Department Spokesman Richard Boucher urged Americans in or near affected areas to call or message home that they are safe.

"For the Americans who are traveling in Asia, or in the South Asian region, or anywhere that's a long way or close to where this disaster is, and that is to call your mother," he said.

Many thousands of U.S. citizens were among those spending year-end holidays at resorts around the Indian Ocean. Mr. Boucher said a special telephone hotline set up by the State Department is receiving 400 calls an hour from worried family members.