YANGON -- More than 22,000 people were killed in Myanmar's devastating cyclone, the government said Tuesday, with thousands more feared dead after the storm left rice fields littered with corpses.
Tens of thousands are still missing four days after the storm slammed into the southern coast, the government said late Tuesday as it announced the sharply increased death toll on state television.
Aid workers were racing to deliver food and water to the worst-hit Irrawaddy delta region, which was submerged by floodwaters, leaving scenes of utter devastation and desperate homeless survivors running low on food and water.
But with the clock ticking four days after the storm hit, Myanmar's reclusive military rulers insisted foreign aid experts would still have to negotiate with the government to be allowed into the isolated nation.
There were also fears that the death toll could rise further, with state media giving no details of casualties in three of the regions affected by the cyclone.
"According to the information as of 12 noon today, 21,793 people were killed and 40,695 were missing in Irrawaddy division, while 671 were killed, 670 were injured and 359 people were missing in Yangon division," state television said late Tuesday.
The government also said it would proceed this weekend with a constitutional referendum as part of its slow-moving "road map" to democracy, except in the areas hardest hit by the disaster.
In its first news conference since tropical cyclone Nargis barrelled into the Irrawaddy river delta early Saturday, the government said many people died from a 12-foot (3.5-metre) tidal wave that slammed into the area.
Social Welfare Minister Maung Maung Swe told reporters that most of the town of Bogalay, one of the delta areas that bore the brunt of the storm's force, had simply been washed away.
"Ninety-five percent of the houses in Bogalay were destroyed," he said. "Many people were killed in a 12-foot tidal wave."
Satellite images from US space agency NASA showed virtually the entire coastal plain of the country, once known as Burma and now one of the poorest nations on the planet, under water.
Christian relief organization 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 below.
"They saw the dead bodies from the helicopters, so it's quite overwhelming," Kyi Minn, an adviser to World Vision's office in Myanmar's main city of Yangon, told Agence France-Presse 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.
Myanmar's pro-democracy opposition urged the ruling junta to provide "effective assistance" to those in need and said it was "extremely unacceptable" for them to go ahead with the referendum.
The National League for Democracy (NLD) said the regime had yet to provide meaningful assistance to hundreds of thousands of victims four days after the storm hit.
"We haven't seen effective assistance to storm victims, even though the authorities have declared (regions) as disaster zones," the National League for Democracy said.
Aid groups were rushing to bring food, clean water, clothing and shelter into the country, whose military rulers have long spurned most of the outside world -- and prevented many aid groups from operating in the isolated nation.
In Geneva, the United Nations said it had a disaster-assessment team in neighboring Thailand still awaiting entry visas -- while the government underlined that foreign relief experts would not be allowed in automatically.
"For expert teams from overseas to come here, they have to negotiate with the foreign ministry and our senior authorities," Maung Maung Swe said.
Relief officials warned that as time went on, fears were mounting about the spread of disease -- on top of the logistical problems of getting aid to many regions that are both remote and densely populated.
"Getting it out to the affected populations will be a major challenge, given that there is widespread flooding," said Richard Horsey, a spokesman for the UN Office for the Coordination of Humanitarian Affairs in Bangkok.
"The urgent need is for shelter and for water. Without clean drinking water, the risk of disease spreading is the most serious concern."
Brigadier General Kyaw Hsan, the secretive regime's information minister, said the country was "greatly thankful" for the offers of help that have been pouring in.
But US First Lady Laura Bush, a longtime critic of the military that has run the country for 46 years, said the government had not done enough to warn citizens that the storm was approaching.
The UN's disaster reduction agency was also critical.
"Looking at the number of deaths, it leads us to think that an early warning system had not been put in place," an agency spokeswoman said. "Obviously many people did not have time to evacuate."