Burma, renamed Myanmar by the ruling military junta, agreed to accept more American aid, officials said Tuesday, opening the door for what could be a massive relief operation as the U.N. warned that less than a quarter of victims' needs are being met 10 days after the devastating cyclone struck.

Logistical bottlenecks, poor infrastructure and restrictions imposed by Burma's isolationist junta were delaying the desperately needed aid for some 2 million severely affected survivors of the May 3 cyclone.

The government says about 62,000 people are dead or missing, but the U.N. has suggested the death toll is likely to be more than 100,000.

While the survivors — mostly poor peasants who grew rice for their livelihood — face disease and starvation, the authoritarian junta continued to bar nearly all foreigners experienced in managing such catastrophes.

It has largely only allowed supplies from the outside. Two U.S. planes and a U.N. convoy have already delivered aid. In an apparent concession, the junta seemed set to allow U.S. supply planes to continue to land Wednesday.

But armed police checkpoints were set up outside Rangoon, the main city, on the roads to the hard-hit Irrawaddy delta, and all foreigners were being sent back by policemen who took down their names and passport numbers.

"No foreigners allowed," a policeman said Tuesday after waving a car back.

Despite the junta's restrictions, countless images of the misery in Irrawaddy have already stirred the world.

The survivors, who have become refugees in their own land, are packed into Buddhist monasteries or camped in the open, drinking dirty water contaminated by dead bodies and animal carcasses. Food and medicines are scarce.

People complain that the junta's soldiers are handing out rotten food while keeping the best for themselves. Thousands of children are orphaned and suffering from fever, diarrhea and respiratory infections.

"There is obviously still a lot of frustration that this aid effort hasn't picked up pace and gotten under way as quickly as it should have," said Richard Horsey, the spokesman of the U.N. humanitarian operation in Bangkok, Thailand.

He said the U.N.'s World Food Program is getting in 20 percent of the food aid needed. "That is a characterization of the program as a whole. We are not reaching enough people quickly enough," he said.

U.N. Secretary-General Ban Ki-moon has also criticized the military leaders for their "unacceptably slow response" to the crisis.

Hundreds of tons of aid has been flown in from around the world, including by the U.N., but the poorly equipped Rangoon airport is incapable of processing the cargo quickly enough. The logistics of moving the aid out are causing other bottlenecks with the junta insisting on using only the few helicopters it has at its disposal.

After Burma allowed a U.S. Air Force C-130 cargo plane into its main city, Yangon, on Monday, the United States sent in one more cargo plane Tuesday with 19,900 pounds of blankets, water and mosquito netting. A third flight was to take in a 24,750-pound load.

U.S. Marine Lt. Col. Douglas Powell said the situation remains fluid, but that flights were expected to continue after Tuesday, which appears to broaden the original agreement for three flights on Monday and Tuesday.

On Monday, Burma told the United States —— the fiercest critic of the junta's human rights record — that basic needs of the storm victims are being fulfilled and that "skillful humanitarian workers are not necessary."

President Bush later told CBS News that the world should be angry and condemn the military government.

"Here they are with a major catastrophe on their hands, and (they) do not allow there to be the full kind of might of a compassionate world to help them," Bush said.

The U.S. military, which has already brought forces to the region for its annual Cobra Gold exercise, has 11,000 troops, at least four ships and potentially dozens of cargo planes nearby that are ready to start assistance operations.

The operation has already been named — Joint Task Force Caring Relief. But officials say they will not push ahead without the approval of Burma's military rulers.

Thai Prime Minister Samak Sundaravej plans to go to Burma on Wednesday to meet with junta officials and urge them to issue more visas to foreign experts, Thai Foreign Minister Noppadon Patama told reporters.

The first U.N. aid convoy to reach Burma overland arrived Monday evening from Thailand with more than 20 tons of tents and plastic sheets.

Andrew Kirkwood of Save the Children, in a conference call with reporters, lauded Burma's private sector for "picking up a lot of the slack" by selling aid groups clothing, materials for shelter and other relief supplies at cost price.

Yangon was pounded by heavy rain Monday and more downpours were expected throughout the week, further hindering aid deliveries. But for many, the rainwater was the only source of clean drinking water.

Britain's opposition Conservative Party leader David Cameron, meanwhile, called for airdropping aid into Burma even without the junta's approval.

"The sands of time are running out," he told BBC Radio.

The idea, supported by some other prominent personalities, has been dismissed by the U.S.

Horsey, the U.N. spokesman, said such a move poses both "political" and "practical" challenges.