As many as 350 people were feared dead after a tropical cyclone with winds up to 150 miles per hour slammed into Myanmar over the weekend, according to local media CNN reports.
"We believe hundreds of people are dead," said Khin Maung Win with the Democratic Voice of Burma -- a broadcast media group run by opposition expatriates. "The entire lower Burma is affected. In some areas, entire villages disappeared."
The activist group opposed the military rule in Myanmar, formerly known as Burma.
The ruling junta declared a state of emergency in five regions: the city of Yangon, Irrawaddy, Pegu and the states of Karen and Mon. All flights to Yangon, the former capital, were canceled. Learn more about Myanmar "
Cyclone Nargis tore off roofs, uprooted trees and downed power lines.
The storm ripped through the sprawling river delta city of Yangon for more than 10 hours -- from Friday night until Saturday noon, said Burma Democratic Concern. Video Watch the cyclone hammer Yangon "
By Sunday, many parts of the city were without electricity. Phone connections were also down in most areas, making it difficult to assess the extent of the damage.
"Most Burmese with whom we've been in touch report they lost their roofs, although so far everyone we have been able to contact reports that they and their families are safe," said a Yangon-based diplomat who requested anonymity because he was not authorized to speak to the media.
Pictures from inside the country showed a cyclone-ravaged region with tin huts crushed under trees. Bicyclists navigated around large branches that littered the deserted roads.
A man with his pant legs rolled up waded through knee-deep water and strained to clear massive limbs that were blocking the entrance to a house.
"The cleanup is beginning, but this will take a long time," the diplomat said. "The damage around town is intense." Photo See photos of the destruction "
"Fuel is not easily available. International emergency assistance would be needed within seven days. There is no food for eating," Win said.
Food prices -- already on a dramatic rise -- climbed further. Long lines could be seen at gas stations in Yangon. Many of the stations were operating on generators. At one gas station more than 100 buses lined up to refill.
"International emergency assistance would be needed within seven days," the diplomat said.
The junta has scheduled a May 10 referendum on a new constitution for the country, which came under sharp criticism from many nations for using force to suppress pro-democracy protests last year.