Burma's military government has declared a three-day mourning period for victims of Cyclone Nargis, which took tens of thousands of lives when it hit the nation's Irrawaddy Delta May 3.

State media announced Monday that flags will be lowered to half-staff during the mourning period, which begins Tuesday.

Also Monday, Burma agreed to let its Southeast Asian neighbors oversee an international effort to bring foreign medical teams and aid to areas hard-hit by the storm. That breakthrough came during an emergency meeting of the Association of Southeast Asian Nations in Singapore.

Singapore's Foreign Minister George Yeo said that while Burma has agreed to accept nearly 300 medical personnel from ASEAN countries, it does not mean there will be uncontrolled access.

Burma has been resisting requests to send in foreign aid workers, and international aid officials warn more relief is needed to prevent starvation and disease.

The United Nations and ASEAN will host a joint conference in Rangoon next week to seek international support and financial aid for those affected by Nargis. Burmese officials say the death toll from Nargis is nearly 78,000, and that nearly 56,000 more people are missing.

The meeting also will focus on longer-term recovery efforts. Burmese officials say losses from the storm could be up to $10 billion.

Burma allowed U.N. humanitarian chief John Holmes to tour the Irrawaddy Delta Monday. The government announced it will let small groups of representatives from several countries visit the cyclone-hit delta in the coming days.

These moves come as U.N. Secretary-General Ban Ki-moon prepares to travel to Burma on Thursday. Mr. Ban is expected to visit areas affected by the disaster, but it is not clear whether he will meet with the country's top leader, General Than Shwe.

Burmese state television Monday showed General Than Shwe making his second visit to the disaster zone, traveling to some of the hardest-hit areas for the first time. Until Sunday, he had not made a single remark or public appearance about the disaster.

Some information for this report was provided by AFP, AP and Reuters.