Four days after the massive Indian Ocean earthquake and tsunamis, rescuers are hoping to finally reach the last remaining pockets of devastation. More than 80,000 people are now known to have died, but that number is still rising as more bodies are pulled from the wreckage in many of the affected countries.

Last Sunday's earthquake and the tsunamis it caused look to have caused one of the world's worst natural disasters ever, with aid agencies predicting that more than 100,000 people were killed, with millions more affected.

Some areas are still proving difficult to reach.

"We have not yet reached several of the islands - some of the Maldives islands, some of the islands outside Sumatra, some of the other islands in the ocean, several communities in Sumatra - we haven't even reached yet," said Jan Egeland, United Nations disaster relief coordinator.

He said that among areas that have been reached, Banda Aceh, the regional capital of Aceh Province on the northern tip of Indonesia's Sumatra Island, suffered worst. Relief workers are still trying to collect bodies of some of the 15,000 estimated to have died there.

Aid is coming into the province, but shortages of trucks and fuel and destruction of roads are hampering its distribution.

More than half the dead were on Sumatra, which suffered from the double blow of the massive earthquake, which collapsed many buildings, and then tsunamis that reached as high as 10 meters.

Around the Indian Ocean, international and local aid efforts are starting to deliver assistance to the millions who lost everything. The United States, India, Japan and Australia have formed an international coalition to coordinate the aid program, and two U.S. carrier groups are steaming towards the worst affected areas to render assistance.

So far donor nations have pledged more than $200 million in aid.

But the United Nations has warned that unless supplies can be delivered, the region risks outbreaks of such diseases as cholera and typhoid, which could kill as many people as the initial disaster.

In Thailand, almost 2,000 people - many of them foreign tourists - have been confirmed dead. But a further 6,000 are missing, and hopes of finding them alive are fading. Thai Prime Minister Thaksin Shinawatra says the search will continue.

"We will keep on going because we still have a lot of corpses to be discovered and it will take some time," he said.

In India, the government says thousands of dead are being discovered in the low-lying Andaman and Nicobar Islands, an isolated archipelago that lies due north of the quake's epicenter.

On Thursday, authorities in Southern India issued a new tsunami alert for the entire coastal area affected by the original deluge, sending residents fleeing from their homes after several tremors in the region raised the water level.

In Sri Lanka, predictions of waterborne diseases have begun to become reality. Reports from the south of the country speak of outbreaks of diarrhea, which can be deadly in weakened patients.