The death toll in the contaminated baby formula scandal has risen to four in China, with the death of a baby in northwestern Xinjiang Uygur Autonomous Region, local authorities said on Thursday.

The latest death was at a hospital in the Mongolian Autonomous Prefecture of Bayingolin, the Xinjiang Autonomous Regional Health Department said on its website (www.xjwst.gov.cn), but no more details were given about the victim.

In addition, 86 babies in the region had fallen ill after drinking the milk powder tainted with the chemical melamine, which was believed to have helped to increase protein content, the department said.

About 10.3 tonnes of baby milk powder produced by the dairy giant Sanlu Group had been pulled off shelves in the region, it said.

The scandal has also claimed the lives of three other babies, including two in northwestern Gansu Province and one in eastern Zhejiang Province.

The dairy giant Sanlu based in the Hebei provincial capital Shijiazhuang in north China was the first company exposed in the tainted milk powder scandal. It is 43 percent owned by New Zealand dairy company Fonterra and has been ordered to halt all its production lines.

Tian Wenhua, the sacked board chairwoman and general manager of Sanlu, has been detained by police for questioning.

Nationwide, more than 6,200 infants had developed kidney stones after drinking Sanlu's tainted baby formula, Health Minister Chen Zhu told reporters on Wednesday.

The State Administration of Quality Supervision, Inspection and Quarantine had carried out test samples involving 491 batches of products sold by all 109 companies that produced baby milk powder in the country. The inspectors found melamine in 69 batches of baby milk powder produced by 22 companies.

To date, 18 suspects in Shijiazhuang had been arrested. Six were charged with selling melamine, while the other 12 were dealers suspected of selling contaminated milk to Sanlu, said Shi Guizhong, spokesman for the Hebei Provincial Public Security Department, on Thursday at a press conference.

On Wednesday the mayor of Shijiazhuang Ji Chuntang resigned as a result of the scandal.

Earlier on Tuesday, four officials in the city were fired. They included Zhang Fawang, vice mayor in charge of agricultural production; Sun Renhu, the Shijiazhuang Municipal Animal Husbandry and Fishery Bureau director; Zhang Yi, Shijiazhuang Municipal Food and Drug Administration director; and Li Zhiguo, Shijiazhuang Municipal Bureau of Quality and Technical Supervision director.

(Xinhua News Agency September18, 2008)