Beijing had drastically revised the total number of children sickened by melamine-tainted milk formula to more than five times higher than the Health Ministry's last public count, Xinhua reported. The figures released yesterday by the ministry said that more than 290,000 children were found to have been affected after drinking infant formula produced by Sanlu or other firms, but did not need major treatment. The report said that 51,900 infants had been sent to hospital since the tainted milk scandal broke in September, with 861 still in hospital and 154 seriously ill. It said the ministry had received 11 reports from local authorities of babies who died after drinking the contaminated milk. But so far it has confirmed that only three of these deaths were directly linked to the milk, which contained melamine, an industrial chemical that causes watered-down milk to register a higher protein content in testing. Official media have reported that four infants died. The ministry had not updated figures issued on September 21 until last night. Previously, the official figures were 40,000 children affected plus 12,892 sent to hospital. It then stopped publicising new figures. Overseas media speculated that the real figures must be much higher than those released on September 21. Reports from local media across the country suggested the number of affected children was close to 94,000. An Associated Press report also found that several deaths apparently caused by the tainted milk products were left out of the official toll. Earlier, a government study of more than 2,000 children aged up to three in the Liangzhou district of Wuwei , Gansu province , showed that 17 per cent of babies there had kidney stones serious enough to send them to hospital. The study said about 10 per cent of the sick had not consumed tainted milk products, suggesting other sources of contamination. Beijing has said all the latest milk products were clean and no fresh cases of contamination had been reported for weeks.