Cyclone Nargis swept across Myanmar on May 2 and 3, triggering a huge tidal wave and killing around 28,000 people, according to the military government. The United Nations estimates the death toll at between 63,000 and 101,000.

The dead include 10,000 who perished in just one town, Bogalay, 90 km (50 miles) southwest of Yangon. Authorities say a further 33,000 people are missing, while the U.N. estimate for the missing is 220,000. The United Nations says 1.2 million to 1.9 million people have been "severely affected" by the cyclone.

The powerful cyclone smashed into the low-lying Irrawaddy delta, unleashing a storm surge as high as 12 feet (3.5 metres) which destroyed houses and gave people nowhere to run.

Nargis is the worst cyclone to hit Asia since 1991, when 143,000 people died in Bangladesh.

The casualty count has been rising quickly as authorities reach hard-hit islands and villages in the Irrawaddy delta, the former "rice bowl of Asia" which bore the brunt of the cyclone's 190 km (120 miles) per hour winds.

The scale of the disaster from the devastating cyclone drew a rare acceptance of limited outside help from the country's diplomatically isolated generals, who spurned similar approaches in the aftermath of the 2004 Indian Ocean tsunami.

U.N. officials said upwards of a million people were without shelter or drinking water in the impoverished southeast Asian nation. Nearly half the country's 53 million people live in the five disaster-hit states.

After getting a "careful green light" from the government, the United Nations said it was pulling out all the stops to send in emergency aid such as food, clean water, blankets and plastic sheeting.

Governments and relief agencies around the world have promised more than $10 million worth of aid and technical support. However, a lack of specialised equipment has slowed distribution, and some international aid workers are waiting for visa approval before being able to go into Myanmar.

The government postponed to May 24 a constitutional referendum in the worst-hit areas of Yangon and the sprawling Irrawaddy delta. But it went ahead with the May 10 vote on the charter - part of the army's much-criticised "roadmap to democracy" - in the rest of the country, which has been under army rule for the last 46 years.

Analysts said the disaster could have political fallout for the regime, which prides itself on its ability to cope with any challenge.