Relief aid is flowing into southern Asian countries devastated by Sunday's earthquake and tsunami.
Governments worldwide have pledged tens of millions of dollars to help the victims of the disaster. But while supplies are being airlifted in, top health officials are warning that sanitation problems and disease could double the immediate death toll.
International officials also stress the need for coordination of aid to avoid duplication, bottlenecks and corruption.
Aid agencies say the threat of mosquito-borne diseases such as malaria, as well as illnesses caused by contaminated water, are already present in the region.
The International Federation of Red Cross and Red Crescent Societies has appealed for an additional 44 million dollars in aid. Red Cross officials say Sunday's tragedy is the largest catastrophe the aid group has seen in decades.
The Red Cross has already delivered medical supplies and medicines to Sri Lanka, while India has received thousands of emergency kits.
Red Cross emergency response teams are also being sent to Indonesia to assist with water and sanitation, logistics, basic health and telecommunications.
Information for this report is provided by AP and AFP.