A man stands next to his washed away house in Dedaye, some 48 kilometers south of Rangoon, 07 May 2008

The top U.S. diplomat in Burma says the death toll in that country from Cyclone Nargis may reach 100,000.

Shari Villarosa, charge d'affaires of the U.S. embassy in Burma, spoke with reporters Wednesday by conference call from Rangoon.

She said the 100,000 figure is based on estimates provided by an international non-governmental organization, but declined to name it.

United Nations Secretary-General Ban Ki-moon has urged Burmese authorities to speed up access for aid workers to the estimated one million people left homeless after Cyclone Nargis struck this past Saturday.

The U.N.'s World Food Program Wednesday sent four aircraft loaded with critically-needed food and other relief supplies.

The International Red Cross has called Nargis a monumental disaster and has made an initial appeal for nearly $6 million in aid to help victims in Burma, following what it says is the deadliest storm since 1991.

Photo released by German relief organisation Malteser International shows local aid workers pack medical supplies in Rangoon, 06 May 2008

Aid workers say relief has begun to trickle into the disaster areas.

Military-ruled Burma has welcomed international relief efforts, but has not eased visa and customs procedures. Some aid agencies are growing impatient with the government's slow response in granting clearances for aid workers and supplies. France is suggesting that the United Nations invoke its "responsibility to protect" clause and deliver aid directly to Burma without the ruling military's approval.

The U.S. has urged six Asian countries (Thailand, India, China, Malaysia, Indonesia and Japan) to use their influence on Burma's authorities to allow U.S. troops stationed in the region to provide emergency rescue services.

In the low-lying Irrawaddy River delta, the region hardest hit by the storm, many bridges have collapsed, roads are flooded and large swathes are still completely under water. Aid workers say that to get to more remote areas you have to either walk, cross riverlets by boat or even swim.

Thailand, China, India and Indonesia are flying in relief supplies as the United States and Australia wait for the Burmese government to accept their offers of relief support.

Some information for this report was provided by AFP and.