Burma has faced international appeals to allow more help
The first UN aid flights have arrived in Burma, bringing much-needed relief to some of the one million people left homeless by Cyclone Nargis.
The flights had been delayed because of Burma's reluctance to accept help, causing growing international concern.
The US says it has not yet been given permission to fly aid into Burma - despite earlier reports that it had.
Burmese state media say 22,980 people were killed by Nargis but there are fears the figure could rise to 100,000.
The cyclone smashed into the low-lying Irrawaddy delta region on Saturday.
The BBC's Paul Danahar, who is in southern Burma, says he has seen the terrible trail of destruction, with survivors desperately searching for shelter.
Normally after a natural disaster, he says, roads are choked by the relief effort, but those into the Irrawaddy delta are empty.
In the biggest city, Rangoon, a patchy recovery effort is under way, but power is lacking almost everywhere, fuel stocks are running low, and only a handful of lorries can be seen setting off with aid supplies.
A woman in the town of Labutta, near the coast south-west of Rangoon, told the BBC's Burmese radio service that 14 villages in the area had been swept away by storm waves.
After surveying the scene from a boat she said: "In some of the fields we saw many dead bodies, whole families of six people. There are many bodies of dead animals... They're decomposing and nobody is doing anything about collecting them."
Opposition politician Dr Myo Nyunt told the BBC: "The wells in the town are contaminated, they're stinking, the people here need clean water, food and tarpaulin sheets for shelter."
The first UN relief plane arrived in Rangoon on Thursday from Italy, carrying high-energy biscuits, medicine and other supplies.
It was followed later by a second flight that originated in Bangladesh.
Two more UN flights are expected to land later on Thursday.
The UN World Food Programme said concern about the military siphoning off aid was one reason for the delay.
WFP regional director Anthony Banbury said: "We will not just bring our supplies to an airport, dump it and take off."
The UN said four members of a disaster assessment and co-ordination team had now been cleared to travel to Burma, but a fifth member of the team was still awaiting a visa.
UN spokeswoman Elizabeth Byrs said the move "shows a certain openness so far, but it is still too slow. Our country team [in Burma] is over-stretched".
Meanwhile, the US ambassador to Thailand, Eric John, called a news conference to address the issue of aid flights.
"This morning, we and our Thai allies thought we had a decision from the Burmese leadership to let the C-130 (Hercules transport aircraft) in. As of now, we don't have that decision," he said.
"I don't know whether they rescinded the decision or if there was a miscommunication."
The BBC's Jonathan Head in Bangkok says Burma's generals have always been intensely suspicious of outside interference and the US has all but called for regime change in Burma.
If countries were allowed to begin aid flights, our correspondent says, Burma could experience the biggest international presence in its recent history.
While flights from Western agencies have been held up, however, Burma's regional neighbours, including India and Thailand, have already flown in aid, while planes from Bangladesh and Indonesia are en route.
The regional Association of South-East Asian Nations had earlier said it was trying to communicate to Burma's military regime the sense of urgency.
China, a close ally of Burma, has also urged it to work with the international community. Foreign ministry spokesman Qin Gang added that Beijing would raise its relief aid to $5.3m (£2.7m).
UK aid agencies have launched an urgent joint appeal to raise funds for victims. The Disasters Emergency Committee said the need for aid was "immediate and vast".
The UK government said Burma was giving out "mixed signals" on access for aid agencies, with some being granted visas and others still waiting.
Burmese troops are pushing into the affected areas but our correspondent Jonathan Head says their resources are inadequate to deal with a disaster of this magnitude.
Destruction in the town of Labutta
On Wednesday, the top US diplomat in Burma said that the number of deaths could be much higher than reported.
Burmese state media say 22,980 people have been confirmed dead and another 42,119 are missing.
But Shari Villarosa, the charge d'affaires of the US embassy in Burma, said the death toll could reach or exceed 100,000, based on information from a non-governmental organisation that she would not name.
A local military official, Tin Win, told AFP news agency 80,000 had died in the remote district of Labutta alone.
There are reports that the Rangoon home of opposition leader Aung San Suu Kyi, who has been under house arrest for 12 of the past 18 years, was damaged in the cyclone but that she is unhurt.
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