DAMAGE ASSESSMENT: Fallen branches and an upended telephone booth litter the roadside in Yangon, which was less badly affected than the delta swamplands. The danger of waterborne diseases is now a major concern. -- PHOTO: AP

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Several other reasons have also been cited for the scale of the disaster, including the destruction of mangrove forests that acted as a buffer against the sea, the lack of an early- warning system and a tidal wave that came in the wake of the killer storm.

Based on a satellite map made available by the United Nations, the storm's damage was concentrated over an estimated 30,000-sq-km area along the Andaman Sea and Gulf of Martaban coastlines - less than 5per cent of the country.

But the affected region is home to nearly a quarter of Myanmar's 57million people.

Aid workers say delivering food, clean water and other supplies to far-flung villages will require an intensive response.

'Our fear is that many in the rural population have been cut off,' said Mr Paul Risley, spokesman in Asia for the World Food Programme, a UN agency. 'In some villages, 90per cent of shelter was destroyed or damaged.'

'They saw the dead bodies from the helicopters, so it's quite overwhelming,' MR KYI MINN, an adviser to World Vision's office in Yangon RELATED LINKS  PATH OF DESTRUCTION

Witnesses yesterday described rice fields littered with corpses, and there are fears the official death toll of more than 22,000 will rise further as tens of thousands remain missing.

Christian relief organisation World Vision, one of the few international agencies allowed to work inside Myanmar, said its teams had flown over the most affected regions and witnessed horrific scenes on the ground.

'They saw the dead bodies from the helicopters, so it's quite overwhelming,' Mr Kyi Minn, an adviser to World Vision's office in Myanmar's main city of Yangon, told AFP in Thailand by telephone.

'The impact of the disaster could be worse than the (2004 Asian) tsunami because it is compounded by the limited availability of resources on top of the transport constraints,' he said.

Save The Children, another relief agency allowed to operate in the country, said it expected the toll to climb as high as 50,000.

'If at this stage, only four days in, the government is telling us the numbers are already reaching over 20,000 and there are 40,000 people missing, I think it could well go higher,' spokesman Dan Collinson told AFP.

'I wouldn't be surprised if it went as high as 50,000.'

Aid agencies reported their assessment teams had reached some devastated areas but getting in supplies and large numbers of aid workers would be difficult.

Mr Richard Horsey, the Bangkok-based spokesman for the UN Office for the Coordination of Humanitarian Aid, said the delta was riddled with waterways, but these were not easily accessible, even during normal times.

'The big concern is waterborne diseases. So that's why it's crucial to get safe water in. Then mosquito nets, cooking kits and clothing in the next few days,' he said. 'Food is not an emergency priority. Water and shelter are.'

Asean Secretary-General Surin Pitsuwan said the destruction of mangrove forests that served as a buffer against the sea was partly to blame for the huge death toll.

'Why the impact is so severe is because of the increase of the population,' he said.

This has led to an 'encroachment into the mangrove forests which used to serve as buffer between the rising tide, between big waves and storms and the residential area,' he said in Singapore.

'All those lands have been destroyed. Human beings are now direct victims of such natural forces.'

Questions were also being raised yesterday about inadequate warnings on the approaching storm, although Indian meteorologists insisted they had given Myanmar a 48-hour warning before the cyclone struck land.

'Forty-eight hours before Nargis struck, we indicated its point of crossing (landfall), its severity and all related issues to Myanmarese agencies,' Indian Meteorological Department spokesman B.P. Yadav said.

The department is mandated by the United Nations' World Meteorological Organisation to track cyclones in the region.

Myanmar Minister for Relief and Resettlement, Maung Maung Swe, told reporters yesterday that the high death toll was caused by a massive wave that gave people nowhere to run.

'More deaths were caused by the tidal wave than the storm itself,' he told a news conference.

'The wave was up to 3.5m high and it swept away and inundated half the houses in low-lying villages,' he said, giving the first detailed description of the disaster. 'They did not have anywhere to flee.'

In Yangon, power remained cut for a fourth day for almost all its 6.5million residents, while water supplies were restored in only a few areas.

Buddhist monks and Catholic nuns wielding knives and axes joined residents in clearing roads of fallen ancient trees that were once the city's pride.

Of the dead, only 671 were in Yangon and its outlying districts, according to state radio. The rest were all in the vast swamplands of the delta.

NEW YORK TIMES, ASSOCIATED PRESS, AGENCE FRANCE-PRESSE, REUTERS