The first United Nations relief flights started to arrive on Thursday for cyclone victims in military-ruled Myanmar as a US diplomat said that more than 100,000 people may have been killed.
The cyclone slammed into coastal towns and villages in the rice-growing Irrawaddy delta southwest of Yangon on Saturday, the most devastating storm to hit Asia since 1991, when 143,000 people were killed in neighbouring Bangladesh.
Witnesses reported that villages were destroyed and people fought for survival by clutching trees as the storm brought walls of water charging inland from the sea.
Aid has been trickling in from other Asian nations, although frustrated governments and relief agencies are putting increasing pressure on Myanmar's reclusive military rulers to throw their borders wide open to as much help as possible.
Thailand, Japan, India, China, Singapore and Indonesia were all flying in assistance.
"The first plane has arrived with food supplies and three other flights were scheduled this morning," said Paul Risley, spokesman for the U.N. World Food Programme in Bangkok.
Reports of cyclone damage in a country that used to be the world's largest rice exporter added to worries about tight global supplies of the grain.
Richard Horsey of the U.N. Office of the Coordination of Humanitarian Affairs said in Bangkok that 5,000 square km (1,930 square miles) of the delta were under water.
But the government insists it has enough reserves, although the the U.N.'s Food and Agriculture Organisation said damage to crops and stores in the delta rice bowl could mean that Myanmar will need short-term imports and miss its 2008 export targets.
At the United Nations in New York, John Holmes, U.N. undersecretary-general for humanitarian affairs, said four Asian aid workers who did not need visas would get in but other U.N. aid workers were still waiting for travel permits.
The United States and other Western countries have imposed tough sanctions against Myanmar over its human rights record, punitive measures that have antagonised the government.
The Myanmar military's own aid operation has moved up a gear with some helicopter drops, but land convoys to the inundated Irrawaddy delta were nowhere to be seen, a Reuters witness said.
State media are reporting a death toll of 22,980 with 42,119 missing, although diplomat and disaster experts said the real figure from the massive storm surge that swept into the Irrawaddy delta is likely to be much higher.
"The information that we're receiving indicates that there may well be over 100,000 deaths in the delta area," Shari Villarosa, charge d'affaires of the U.S. embassy in Myanmar, told reporters in Washington.
The U.N.'s Holmes said the toll could not be independently verified, but "it would not surprise me if they continued to rise and maybe rise very significantly".
Washington, a vocal critic of the junta that has ruled the former Burma for more than four decades, said humanitarian access should not be a political matter.
"What remains is for the Burmese government to allow the international community to help its people. It should be a simple matter. It is not a matter of politics," Secretary of State Condoleezza Rice told reporters in Washington.
Political analysts and critics of 46 years of military rule said the cyclone may have long-term implications for the junta, which is even more feared and resented since last September's bloody crackdown on Buddhist monk-led protests.
For the moment, though, the mood in rubble-strewn Yangon, a city of five million people, is one of resignation rather than revolution.
"There won't be demonstrations," one taxi driver told Reuters on Wednesday. "People don't want to be shot."