The four-nation coalition would lead the international responseto the catastrophe that has left more than 80,000 people dead, Bush told reporters after emerging from a holiday vacation at his Texas ranch to make his first comment on the four-day-old disaster.He urged other nations to join.

Bush said he phoned the leaders of stricken countries to solicit specific needs and assure them the initial aid package "isonly the beginning of our help."

The United States has pledged 35 million US dollars in assistance and rehabilitation, with additions expected as assessments of damage are collected.

Besides, the Pentagon has committed six cargo planes and nine reconnaissance planes, and has diverted warships from Hong Kong and Guam to survey damage and help with recovery.

Three military scouting teams began arriving Wednesday in Thailand, Sri Lanka and Indonesia.

For now, the United States is focusing on water and sanitation in the disaster-affected region. "That is the greatest risk to people's lives," said Andrew S. Natsios, director of the US Agencyfor International Development.

The death toll from a massive undersea earthquake and subsequent tsunami striking South and Southeast Asia on Sunday is expected to exceed 100,000, Natsios says.

Twelve Americans were reported killed in the devastated coast areas across Asia, seven in Sri Lanka and five in Thailand.