"The information that we're receiving indicates that there may well be over 100,000 deaths in the delta area," Shari Villarosa, charge d'affaires of the U.S. Embassy in Myanmar, formerly Burma, said during a news conference.

The Irrawaddy Delta is the low-lying region that caught the brunt of the cyclone when it struck.

Speaking from Yangon, formerly known as Rangoon, Villarosa said the 100,000 estimate was provided by an international non-governmental organization, and wasn't an official count, The Washington Post reported.

Revised official estimates place the number of dead at 70,000, The Post said. The military government said most people died from the 12-foot storm surge.

"The situation in the delta sounds more and more horrendous," Villarosa said, citing "a very real risk of disease outbreaks" in the absence of clean water.

Emergency supplies began arriving in Myanmar Wednesday in the form of airplane shipments from India and food drops by military helicopters in the flooded regions.

A U.N. official said the organization received permission to begin sending its own shipments, but was awaiting visas for its workers.

U.S. Secretary of State Condoleezza Rice said the United States urged countries in the region to press the military junta to admit more relief workers and supplies, Voice of America reported.

"What remains is for the (Myanmar) government to allow the international community to help its people," Rice said. "This is not a matter of politics. This is a matter of a humanitarian crisis."