Food, water and medical services were being identified as the most urgent needs of the Haitian population Friday, as time was rapidly running out for search and rescue missions in the country, following a massive earthquake, reported the dpa. "Thousands of victims of Tuesday"s devastating earthquake have had to spend a third night out in the open, while the chances of locating further survivors continue to diminish," the International Committee of the Red Cross (ICRC) said. Search and rescue teams say 48 to 72 hours is the key window for reaching survivors, as humans cannot generally live without water for longer periods. It remained difficult to move into the country heavy machinery needed to clear collapsed buildings and reach victims buried beneath rubble. "No figures for the dead or injured are available but they are likely to be very high," the United Nations said. A top official warned that the response would be "limited" and "takes time," even as operations were being stepped up. "The reality is that getting the quantities of supplies, equipment and expertise that are so desperately needed on the ground inevitably takes time," said John Holmes, the UN"s chief of emergency relief. While some food was reaching Port au Prince from agricultural areas nearby, the prices had shot up exponentially, leaving much of Haiti"s impoverished people without the means to purchase the basic supplies of vegetables, humanitarian officials in the country said. The lack of electricity and fuel for medical vehicles and generators was also hampering aid efforts. "The three most important needs we have identified now are medical care, food and drinking water," said Stefano Zannini with Medecins Sans Frontieres (Doctors Without Borders) in the Haitian capital. "In the MSF hospital we have thousands of people needing surgical intervention," he told reporters by telephone. --More