Health Ministry sources told Reuters just under 80,000 had died in Indonesia's northern Aceh province that was close to the undersea quake, some 28,000 more than previously announced. Two sources said the toll would be officially announced soon.

Aceh, already suffering a prolonged conflict, has emerged as the "ground zero" of Sunday's great earthquake just off its coast. It triggered monstrous waves all the way to Africa that killed thousands more in India, Thailand and elsewhere.

Sri Lanka, severely afflicted, raised its toll on Thursday by just under 3,000 people to 27,268.

Millions of people on Indian Ocean shores scrambled for food and clean water as disease, thirst, hunger and panic threatened survivors of the world's most lethal natural disaster since a cyclone in Bangladesh killed 138,000 people in 1991.

Aftershocks, rumors and an Indian tsunami warning that proved wrong added to the chaos in a still terrified region.

Despite Thursday's spiraling toll, the true scale of the disaster may not be known for weeks, if ever, as rescuers battled to reach remote areas and washed-away towns, and grieving survivors searched for bodies of locals and tourists alike.

The scale that was known grew ever more awesome.

"This isn't just a situation of giving out food and water. Entire towns and villages need to be rebuilt from the ground up," said Rod Volway of CARE Canada, whose emergency team was one of the first into Aceh.

As the world pledged $220 million in cash and sent a flotilla of ships and aircraft laden with supplies, history's biggest relief operation battled with the enormity of the task.

"As many as 5 million people are not able to access what they need for living," said David Nabarro, head of a World Health Organization (WHO) crisis team.

Many villages and resorts are now mud-covered rubble, blanketed with the stench of corpses after the 9.0 magnitude quake, the most powerful in 40 years.

Thousands of bodies rotting in the tropical heat were tumbled into mass graves, but health officials said polluted water posed a much greater threat than corpses.

Holiday-makers were among those caught by surprise. Nearly 5,000 foreigners  half from Sweden and Germany  are missing, many in Thailand, where 710 foreigners have been confirmed dead.