YANGON (AFP) - More than one million homeless in Myanmar were battling to stave off disease and hunger Thursday, but the military government maintained tight limits on foreign assistance six days after a massive cyclone. With death toll estimates near 100,000 and the clock ticking for those who survived, Myanmar's junta - long suspicious of the outside world - came under new pressure to fully open up to help from abroad. Aid was only trickling in despite warnings that specialists were needed to deliver food and water into disaster zones strewn with rotting bodies, and it was unclear if the regime had yet given visas to foreign aid staff. The United States announced it was not sending an aid flight after earlier saying it was, adding to the sense of confusion and frustration over the international relief effort. There are fears that many of those who survived the first tragedy may succumb to a second, falling prey to hunger and disease while the supplies that might save them languish nearby with no way - or no permission - to get in. Aid groups said the country needs hundreds of planeloads of supplies and equipment to cope with Cyclone Nargis, which barrelled into Myanmar overnight Friday, unleashing one of the worst natural disasters in history. They said help was slowly arriving, but not enough - and not quickly enough - for most of those in the stricken southwest Irrawaddy delta who saw their villages ripped apart or washed away. In a rare break from its policy of non-interference in its members' affairs, the Association of Southeast Asian Nations (ASEAN) pressed the junta to soften its stance, as did China, Myanmar's most powerful ally. Around 5,000 square kilometres remain underwater, and more than a million homeless need emergency relief, said Richard Horsey, a Bangkok-based spokesman with the UN's Office for the Coordination of Humanitarian Affairs. Myanmar's agricultural heartland has suffered a huge blow from Cyclone Nargis, with the fishing and farming sectors hit worse than in the Asian tsunami, the UN's food agency said Thursday. "Cyclone Nargis has affected the same areas in the (Irrawaddy) division that were hit by the 2004 tsunami," the Food and Agriculture Organisation (FAO) said in a statement. "This time around, the impact is believed to be far more severe."