London, May 9 : The U.N. World Food Programme (WFP) has halted aid shipments to Burma after two plane loads of food were impounded on arrival by that country's military authorities.
A BBC report said that the Burmese Government had seized tonnes of aid material flown in to help victims of Cyclone Nargis, which has killed tens of thousands of people.
The WFP said it had no choice but to halt aid until the matter was resolved.
Burma's ruling generals have faced mounting criticism over their handling of the crisis.
The UN fears more than 1.5 million people have been affected by the cyclone, with tens of thousands made homeless and vulnerable to disease.
The World Health Organization says access to clean drinking water and outbreaks of communicable diseases such as dengue and malaria are a major concern.
Burmese state media say 22,980 people were killed, but there are fears the figure could rise.
Britain's ambassador to Burma, Mark Canning, said authoritative sources were now speaking of between 63,000 and 100,000 people dead or missing.
Hundreds of thousands of people have no food, water or shelter. International aid agencies on the ground say seven tonnes of high-energy biscuits have been distributed in the delta region, but they have reached only 10 percent of those that need help.
Despite this, Burma's foreign ministry issued a statement on Friday saying it was not ready to allow foreign aid workers to enter the country. The junta said it was happy to accept aid, but insisted it would control the distribution itself.
WFP spokesman Paul Risley said two flights of "critically-needed food aid" - including 38 tonnes of high-energy biscuits - arrived in Burma on Friday but was confiscated.
This delay seems inexplicable even as several countries have come forward willingly with aid packages.
Britain, Japan and the United Nations have pledged to give 10 million dollars each, while the United States and France have come forward with a package of three million dollars each. Australia has pledged 2.8 million dollars.
The UN claims that up to 1.5 million people may have been affected by Cyclone Nargis, which devastated the Irrawaddy Delta region on Saturday.
Burmese state media say 22,980 people were killed, but there are fears the figure could rise to 100,000.
Hundreds of thousands of people have no food, water or shelter. International aid agencies on the ground say they have reached only 10 percent of those that need help.
Human rights groups have urged the generals to postpone a referendum on their much-criticised constitution, due to take place on Saturday.
Thai Prime Minister Samak Sundaravej was due to fly to Burma on Sunday to urge its leaders to allow foreign aid workers in.
A relief flight from Qatar, which had an aid team and a media crew on board, has been turned back.
Reports suggest that the troops have begun to distribute significantly more aid, experts agree that the military regime lacks the resources to co-ordinate an effective relief effort.
Burmese TV reported that four flights carrying supplies from the UN's World Food Programme arrived in Rangoon on Thursday, as did an International Committee of the Red Cross (ICRC) flight.
Reports on Thursday had suggested the US had been granted permission to fly in supplies using military planes - but officials later said no agreement had been reached.