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Burma's isolationist regime blocked United Nations efforts Thursday to airlift urgently needed high-energy biscuits to survivors of a cyclone that may have killed more than 100,000 people, U.N. officials said.

Paul Risley, a spokesman of the U.N's World Food Program in Bangkok, said three flights were waiting to take off from Dubai, Dhaka and Thailand with 50 tons of biscuits. A fourth shipment aboard a scheduled Thai Airways cargo flight was likely to bring some biscuits later Thursday.

He told The Associated Press that the WFP was in "constant touch" with the military junta to obtain the flight clearance for the first major airlift of international aid, but there has been no word from officials.

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Earlier, a statement from WFP in Washington indicated that a green-light for the airlift had been given, saying the planes were scheduled to land in Yangon early Thursday.

Burma's generals, traditionally paranoid about foreign influence, issued an appeal for international assistance after the deadly storm struck Saturday. But they have since dragged their feet on issuing visas to relief workers even as survivors face hunger, disease and flooding in the hardest hit Irrawaddy delta.

A handful of smaller shipments from neighboring countries arrived earlier in the week.

Burma's state media said Cyclone Nargis has killed at least 22,980 people and left 42,119 missing, but a top U.S. diplomat said Wednesday that more than 100,000 may have perished.

"We are in constant discussion with them in Yangon, and we expect to receive clearance," Risley said.

"It is enough of a challenge that visas are being held up for bringing in experience international relief workers, but it is specially frustrating that critically needed food aid is being held up," he said.

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Burma's state television Thursday showed Prime Minister Lt. Gen. Thein Sein distributing food packages to the sick and injured in the delta and soldiers dropping food over villages. The date of the distributions was not given.

Indian navy vessels and planes from Japan, Thailand, Singapore and Laos and Bangladesh had arrived in recent days with medicine, candles, instant noodles, raincoats and other relief supplies, the television said.

State radio said "unscrupulous elements" in Yangon were spreading rumors of an impending earthquake, a second cyclone and looting in the country's largest city. Residents say that some looting did occur at markets and stores after the storm hit.

It appeared the regime was trying both to calm the population and stop any gatherings that might turn into political agitation against widely detested military rule.

Although most Yangon residents were preoccupied in trying to restore their lives in wake of the storm, activists using the cover of an almost total power outage have scribbled fresh graffiti on the city's overpasses.

The graffiti included "X" marks — a symbol for voting "no" to a military-backed constitution which is up for a referendum Saturday. Voting has been postponed until May 24 in Yangon city, some outlying areas and parts of the delta because of the storm's destruction.

Entire villages in the Irrawaddy delta were still submerged from the storm, and bloated corpses could be seen stuck in the mangroves. Some survivors stripped clothes off the dead. People wailed as they described the horror of the torrent swept ashore by the cyclone.

"I don't know what happened to my wife and young children," said Phan Maung, 55, who held onto a coconut tree until the water level dropped.

A spokesman for the U.N. Children's Fund said its staff in Burma, renamed Myanmar by the ruling military junta, reported seeing many people huddled in roughly built shelters and children who had lost their parents.

"There's widespread devastation. Buildings and health centers are flattened and bloated dead animals are floating around, which is an alarm for spreading disease. These are massive and horrific scenes," Patrick McCormick said at UNICEF offices in New York.

American diplomat Shari Villarosa, who heads the U.S. Embassy in Yangon, said the number of dead could eventually exceed 100,000 because safe food and water were scarce and unsanitary conditions widespread.

A few shops reopened in the Irrawaddy delta, but they were quickly overwhelmed by desperate people, said Risley, quoting his agency's workers in the area.

"Fistfights are breaking out," he said.

A Yangon resident who returned to the city from the delta area said people were drinking coconut water because there was no safe drinking water. He said many people were on boats using blankets as sails.

Some aid workers said heavily flooded areas were accessible only by boat, with helicopters unable to find dry spots for landing relief supplies.

"Basically the entire lower delta region is under water," said Richard Horsey, the Thailand-based spokesman for the U.N. Office for the Coordination of Humanitarian Aid.