An international relief operation was being mobilized as the Myanmar government raised its estimate of the death toll from Cyclone Nargis on Tuesday to nearly 22,500 with a further 41,000 missing, nearly all of them from a massive storm surge that swept into the Irrawaddy delta. Of the dead, only 671 were in the former capital, Yangon, and its outlying districts, state radio said, confirming Nargis as the most devastating cyclone to hit Asia since 1991. “More deaths were caused by the tidal wave than the storm itself,” Minister for Relief and Resettlement Maung Maung Swe told a news conference in the rubble-strewn city of five million, where food and water supplies are running low. “The wave was up to 12 feet high and it swept away and inundated half the houses in low-lying villages,” he said, giving the first detailed description of the weekend cyclone. “They did not have anywhere to flee.” Information Minister Kyaw Hsan said the military were “doing their best”. The junta said it would postpone to May 24 a constitutional referendum in the worst-hit areas of Yangon and the sprawling delta. The disaster drew a rare acceptance of outside help from the diplomatically isolated generals. US President George W. Bush urged the regime to accept US disaster response teams that so far have been kept out, and said the United States stood ready to “do a lot more” to help. “The military junta must allow our disaster assessment teams into the country,” Bush told reporters. Bernard Delpuech, a European Union aid official in Yangon, said the junta had sent three ships carrying food to the delta region. Aid agency World Vision in Australia said it had been granted special visas to send in personnel to back up 600 staff in the impoverished country. China said it would send one million dollars in emergency aid in batches. Thailand airlifted more than 400,000 dollars' worth of food, drinking water and medical supplies. Japan offered 28 million yen (270,000 dollars) in emergency aids. Singapore expressed solidarity and pledged 200,000 US dollars in aid. Australia said it was “ready, willing and able” to send aid, while South Korea announced it would provide emergency materials. UN Secretary General Ban Ki-moon said the organization “will do whatever (necessary) to provide urgent humanitarian assistance”. Meanwhile, The Indian Meteorological Department (IMD), which had been monitoring the deepening depression over the Bay of Bengal since late last month, said it gave 48 hours warning that the cyclone would barrel into Myanmar.