YANGON, Myanmar — U.N. Secretary-General Ban Ki-moon flew into Myanmar's disaster zone today as he pressed the country's leaders to open the doors to critical international aid for some 2.5 million cyclone survivors.

In a meeting with Prime Minister Thein Sein, Ban stressed foreign aid experts needed to be rushed in because the crisis exceeded Myanmar's national capacity, according to a U.N. official at the talks.

Ban was then flown by helicopter to the cyclone-ravaged Irrawaddy delta, the country's rice bowl, where most of the 78,000 deaths from Cyclone Nargis occurred. Another 56,000 are officially listed as missing.

As Ban began his visit, foreign aid agencies stressed the need to quickly reach some 2.5 million survivors, many of them suffering from disease, hunger and lack of shelter.

Ban met for nearly 1Z\x hours with Thein Sein as well as with international aid agencies in Yangon, Myanmar's largest city.