Almost 4,000 people were killed and nearly 3,000 others are unaccounted for after a devastating cyclone in Myanmar, a state radio station said Monday.

Foreign Minister Nyan Win told foreign diplomats at a briefing that the death toll could rise to more than 10,000, according to diplomats who spoke on condition of anonymity because the meeting was held behind closed doors.

Tropical Cyclone Nargis hit the Southeast Asian country, also known as Burma, early Saturday with winds of up to 120 mph, leaving hundreds of thousands of people homeless.

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U.N. agencies and independent humanitarian groups rushed Monday to prepare assistance for victims of a devastating cyclone in Myanmar, while awaiting a formal go-ahead from the military regime in the Southeast Asian nation.

The United States said the junta had so far refused to allow an American disaster team in to assess damage to follow up on an emergency U.S. contribution of $250,000.

"That is a barrier to us being able to move forward," deputy State Department spokesman Tom Casey said. "We asked for permission, but the initial response from the government was that they were not inclined to let them in."

German Foreign Minister Frank-Walter Steinmeier, in announcing he was making $773,000 available to German aid groups to help Myanmar, urged the military government "to allow an effective aid operation and to work together with international aid organizations."

Relief agency representatives met in Yangon, Myanmar's biggest city, as well as in Bangkok, Thailand, to assess the damage and prepare supplies.

Laura Blank, spokeswoman for World Vision, said two assessment teams have been sent to the hardest hit areas to determine the most urgent needs.

"This is probably the most devastating natural disaster in Southeast Asia since the tsunami," Blank said, referring to the 2004 disaster that killed around 230,000 people in 12 Indian Ocean nations. "There are a lot of important needs, but the most important is clean water."

Myanmar is not known to have an adequate disaster warning system and many rural buildings are constructed of thatch, bamboo and other materials easily destroyed by fierce storms.

"The government misled people. They could have warned us about the severity of the coming cyclone so we could be better prepared," said Thin Thin, a grocery store owner.

Myanmar's government had previously put the death toll countrywide at 351 before increasing it Monday to 3,939.

The radio station broadcasting from the country's capital, Naypyitaw, said that 2,879 more people are unaccounted for in a single town, Bogalay, in the country's low-lying Irrawaddy River delta area where the storm wreaked the most havoc.

"Our staff has heard that in eight townships, over 95 percent of the land has been severely affected," Pamela Sitko, World Vision's communication relief manager for the Asia-Pacific region, told The Associated Press from Bangkok.

The situation in the countryside remained unclear because of poor communications and roads left impassable by the storm.

"Widespread destruction is obviously making it more difficult to get aid to people who need it most," said Michael Annear, regional disaster management coordinator for the International Federation of the Red Cross in Bangkok.

At a Monday meeting with foreign diplomats and representatives of U.N. and international aid agencies, Myanmar's foreign ministry officials said they welcomed international humanitarian assistance and urgently need roofing materials, plastic sheets and temporary tents, medicine, water purifying tablets, blankets and mosquito nets.

In Washington, the State Department said the U.S. Embassy in Yangon had authorized an emergency contribution of $250,000 to help with relief efforts.

"We have a DART team that is standing by and ready to go into Burma to help try to assess needs there," deputy spokesman Tom Casey told reporters. "As of this moment, the Burmese government has not given them permission, however, to go into the country so that is a barrier to us being able to move forward."

Myanmar Red volunteers already were distributing some basic items, said Matthew Cochrane at the International Federation of the Red Cross and Red Crescent Societies' Geneva headquarters.

The World Food Program has pre-positioned 500 tons of food in Yangon and plans to bring in more relief supplies, said Elisabeth Byrs, spokeswoman for the U.N. Office for the Coordination of Humanitarian Affairs.

U.N. agencies were working with the Red Cross and other organizations to see how it can help those affected by the cyclone. UNICEF spokeswoman Veronique Taveau said the U.N. children's agency alone has five teams assessing the situation in the country.

The cyclone blew roofs off hospitals and schools and cut electricity in Yangon. Older citizens said they had never seen the city of some 6.5 million so devastated in their lifetimes.

With the city's already unstable electricity supply virtually nonfunctional, citizens lined up to buy candles, which doubled in price, and water since lack of electricity-driven pumps left most households dry. Some walked to the city's lakes to wash.

Hotels and richer families were using private generators but only sparingly, given the soaring price of fuel.

Many stayed away from their jobs, either because they could not find transportation or because they had to seek food and shelter for their families.

"Without my daily earning, just survival has become a big problem for us," said Tin Hla, who normally repairs umbrellas at a roadside stand.

With his home destroyed by the storm, Tin Hla said he has had to place his family of five into one of the monasteries that have offered temporary shelter to those left homeless.

His entire morning was taken up with looking for water and some food to buy, ending up with three chicken eggs that cost double the normal price.

Despite the havoc wreaked by the cyclone across wide swaths of the country, the government indicated that a referendum on the country's draft constitution would proceed as planned on May 10.

"It's only a few days left before the coming referendum and people are eager to cast their vote," the state-owned newspaper Myanma Ahlin said Monday.

At the meeting with diplomats, Relief Minister Maj. Gen. Maung Maung Swe said the vote could be postponed by "a few days" in the worst-affected areas. However, the foreign minister intervened to say the matter would be decided by the official referendum commission.

Pro-democracy groups in the country and many international critics have branded the proposed constitution as merely a tool for the military's continued grip on power.

Should the junta be seen as failing disaster victims, voters who already blame the regime for ruining the economy and crushing democracy could take out their frustrations at the ballot box.