However Mr Piazzi, of the UN's office for humanitarian affairs, said some hope remained of locating survivors. Concern is growing for the health of those who have lived through the quake, with disease the latest threat to survivors. The fear of aftershocks has persuaded millions of people to camp out in the open - close to the decomposing bodies of those killed in the earthquake. Most rescue workers are wearing masks, and are being immunised against typhoid. Reports are already emerging of cholera cases in some areas south-east of Istanbul.
International doctors treating the injured say the area is ripe for infection.
Teams are working to chlorinate water, disinfect areas and put recovered corpses in bags before disease starts to spread. Dysentery, diarrhoea and gastroenteritis were starting to strike, said French volunteer Dr Wolff Pierre. Some estimates put the number of people sleeping outside on Thursday night as high as two million. The figure included not only those survivors who have lost their homes, but also the people living in and around Bursa - whose governor, Orhan Tasanlar, warned people to stay outside for the night. Further devastation has been reported after a 20-ft high tidal wave in the Sea of Marmara destroyed large areas of the Degirmendere holiday resort moments after the earthquake on Tuesday.