YANGON, Myanmar - The official death toll nearly doubled to 78,000 from Myanmar's killer cyclone as heavy rains yesterday lashed much of the area stricken two weeks ago, further hampering relief efforts.

Aid workers shackled by the country's military regime struggled to get even the most basic data about the needs of up to 2.5 million survivors. The Red Cross warned that a lack of clean water might swell the ranks of the dead.

Myanmar state television said the official death count from the May 3 cyclone was 77,738, with 55,917 others missing.

The toll was nearly double the 43,000 previously reported, but the TV announcement suggested it might be close to a final figure. It said the government had "carried out search and rescue, and relief work, and collection of data, promptly, immediately and extensively."

The release of the figures led to dire warnings from the United Nations and renewed calls for the military regime to allow international aid workers access to devastated areas.

"More than two weeks after the event, we are at a critical point," said U.N. Secretary-General Ban Ki-moon. "Unless more aid gets into the country - quickly - we face the risk of an outbreak of infectious diseases that could dramatically worsen today's crisis."

The junta maintains it has the situation under control. But after two weeks, the U.N. remains largely in the dark about the situation on the ground.

"We simply don't have the information, and I can't say when we will have it," said Steve Marshall, a U.N. official who just left Myanmar.

The Red Cross has put the death toll as high as 128,000, and the most recent official figures on dead and missing have the U.N. saying the number could easily reach 130,000.

The highest death estimate is carried by the British government's Department for International Development, which says "unofficial estimates suggest the number of dead or missing is in the region of 217,000."

The department said the estimate was reported to it by sources on the ground with knowledge of the situation. The department gave no other details and said the estimates could not be verified immediately.

The U.N. estimates 1.5 million to 2.5 million survivors are in desperate need of food, water, shelter and medical care.