Thousands of children in Burma, also known as Myanmar, will starve to death in two to three weeks unless food is rushed to them, an aid agency warned Sunday as an increasingly angry international community pleaded for approval to mount an all-out effort to help cyclone survivors.

The United Nations said Burma's isolationist ruling generals were even forbidding the import of communications equipment, hampering already difficult contact among relief agencies.

A U.N. situation report said Saturday that emergency relief from the international community had reached an estimated 500,000 people. But the regime insists it will handle distribution to victims of Cyclone Nargis.

U.N. Secretary-General Ban Ki-moon, who has been unable to sway Burma's leaders by telephone, said he was sending U.N. humanitarian chief John Holmes to Burma this weekend.

Holmes was expected to arrive Sunday evening in Burma's largest city, Rangoon, said Amanda Pitt, a U.N. spokeswoman in Bangkok, the capital of neighboring Thailand.

"He's going at the request of the secretary-general to find out what's really going on the ground, to get a much better picture of how the response is going and ... to see how much we can help them scale up this response," Pitt said. Details of the visit, she said, were still being worked out.

The U.N. report said all communications equipment used by foreign agencies must be purchased through Burma's Ministry of Posts and Communications — with a maximum of 10 telephones per agency — for $1,500 each. Importing equipment is not allowed.

State-run radio said the government has so far spent about $2 million for relief work and has received millions of dollars worth of relief supplies from local and international donors. It said the government was distributing assistance promptly and efficiently to the affected areas.

Aid agencies were not convinced.

Save the Children, a global aid agency, said Sunday that thousands of young children face starvation without quick food aid.

"We are extremely worried that many children in the affected areas are now suffering from severe acute malnourishment, the most serious level of hunger," said Jasmine Whitbread, who heads the agency's operation in Britain. "When people reach this stage, they can die in a matter of days."

International outrage mounted over Burma's handling of the disaster.

Britain's prime minister accused authorities in the country of preventing foreign aid from reaching victims and said the military regime cares more about its own survival than it's people's welfare.

"This is inhuman," Gordon Brown told the British Broadcasting Corp.

In one town near Rangoon, tired and hungry refugees stood in the baking sun beside flooded rice paddies, demolished monasteries and thatched huts. With the arrival of each vehicle carrying precious food and water, they jumped with excitement and surged ahead to get a share.

At least they were getting something.

"The farther you go, the worse the situation," said an overwhelmed doctor in the town of Twante, just southwest of Rangoon, Burma's main city. "Near Rangoon, people are getting a lot of help and it's still bad. In the remote delta villages, we don't even want to imagine." The doctor declined to give her name, fearing government reprisal.

The government flew 60 diplomats and U.S. officials in helicopters to three places in the Irrawaddy delta, the hardest-hit area, on Saturday to show them progress in the relief effort.

The diplomats were not all swayed.

"It was a show," Shari Villarosa, the top U.S. diplomat in Burma, told The Associated Press by telephone after returning to Yangon. "That's what they wanted us to see."

A French navy ship that arrived Saturday off Burma's shores loaded with food, medication and fresh water — a potentially lifesaving cargo — was given the now-familiar red light. France's U.N. ambassador, Jean-Maurice Ripert, called it "nonsense."

"We have small boats, which could allow us to go through the delta to most of the regions where no one has accessed yet," he said. "We have small helicopters to drop food, and we have doctors."

The USS Essex, an amphibious assault ship, and its battle group also have been waiting to join the relief effort. U.S. Marine flights to Rangoon from their makeshift headquarters in Utapao, Thailand, continued Saturday — bringing the total to 500,000 pounds of aid delivered — but negotiations to allow helicopters to fly directly to the disaster zone were stalled.

Burma's state-run television, which has repeatedly broadcast footage of generals reassuring refugees calmly sitting in clean tents, announced Friday that the cyclone death toll had nearly doubled to 78,000 with about 56,000 missing.

Aid groups say even those estimates are low.

The international Red Cross says the death toll alone is probably about 128,000, with many more deaths possible from disease and starvation unless help gets quickly to some 2.5 million survivors.

But seeing that help gets to the victims does not appear to be a top priority for Burma's rulers. The military, which took power in a 1962 coup, has even barred foreigners from traveling outside of Rangoon, putting up a security cordon around the city.

Burma has been slightly more open to aid from its neighbors, accepting Thai and Indian medical teams, which arrived Saturday. The 32-member Thai team was expected to travel to the delta in the coming days, said Dr. Surachet Satitniramai, director of Thailand's National Medical Emergency Services Institute.

The Indian team consists of 50 doctors and paramedics from the Army Medical Corp., said Indian Air Force spokesman Wing Cmdr. Manish Gandhi. He could not immediately say if they would be allowed to go to the delta.