China's Health Ministry said six babies may have died after consuming tainted milk powder, up from a previous official toll of three, and announced a six-fold increase in its tally of infants sickened in the scandal — to nearly 300,000.

It was the first time since Sept. 21 that health authorites have revised the total number of babies sickened by milk powered adulterated with the industrial chemical melamine. The previous total was about 50,000.

The ministry said in a statement late Monday that authorities across the country found that 294,000 babies had suffered from urinary problems after consuming milk powder tainted with melamine.

"Most of the sickened children received outpatient treatment only for small amounts of sand-like kidney stones found in their urinary systems, while a part of the patients had to be hospitalized for the illness," the statement said.

Thousands of parents have been clamoring for compensation for their sickened and dead children. The release of the figures raises the question of whether the Health Ministry is getting closer to finalizing a compensation scheme.

Six babies had possibly died, the statement said, with four of the cases recorded in the provinces of Jiangxi, Zhejiang, Guizhou and Shaanxi, and the other two in Gansu province in the northwest.

The ministry said it investigated 11 possible deaths related to melamine-tainted milk and ruled five of them out. It did not give further details nor say whether the three earlier reported deaths were included in the new total.

By last Thursday, 861 babies were still hospitalized with kidney problems caused by contaminated milk powder, down from the previous week's figure of 1,041, the statement said.

The ministry declined phone interviews Tuesday and did not immediately respond to a faxed list of questions from The Associated Press.

The scandal was first reported in September, but the government has said that Shijiazhuang Sanlu Group Co., a dairy firm at the center of the crisis, knew as early as last year that its products were tainted with melamine and that company and local officials first tried to cover it up.

The ministry said it checked into babies who died since September but did not mention deaths that may have happened before then. Some parents have said their babies had died from drinking tainted milk powder but that they were left out of the previous official count.

The scandal prompted authorities to announce a complete overhaul of the country's dairy industry to improve safety. It highlighted the widespread practice of adding melamine — often used in manufacturing plastics — to watered-down milk to fool protein tests. Melamine is rich in nitrogen, which registers as protein on many routine tests.

Though melamine is not believed harmful in tiny amounts, higher concentrations produce kidney stones, which can block the ducts that carry urine from the body, and in serious cases can cause kidney failure.

The scandal spread rapidly as melamine was found in other kinds of dairy products such as liquid milk, yogurt and chocolates. It prompted a string of recalls of Chinese-made milk and products containing milk in dozens of countries. Later investigations also discovered it was being added to animal feed after finding melamine-spiked eggs.

Melamine was also found in a Chinese-made pet food ingredient that killed dogs and cats in North America in 2007.

With the scandal escalating, Chinese leaders have been desperate to clean up the country's image, making dozens of arrests in recent weeks and firing local and even high-level officials for negligence.

Though China has vowed to boost inspections for melamine contamination, experts say it will be difficult to monitor the countless small, illegally operating manufacturers found across the country.

Dairy companies say they have bought new testing labs for melamine, and are trying to consolidate farms that supply their milk in an effort to win back consumer confidence.