Myanmar's military leaders seized aid shipments headed for cyclone survivors and told the top U.S. diplomat there Friday that they're not ready to let in American aid workers despite warnings the country is on the verge of a medical catastrophe.Another 4 inches of rain was forecast to fall next week as more than 1 million people waited for food, clean water, shelter and medicine to reach them. Diplomats and aid groups warned the number of dead could eventually exceed 100,000 because of illnesses and said thousands of children may have been orphaned.