Beijing - Courts in northern China's Hebei province on Friday tried six people accused of crimes linked to melamine-tainted milk powder, which apparently led to the death of at least six infants.

The Intermediate People's Court in Shijiazhuang city tried Zhang Yujun on charges of producing 775.6 tons of melamine-laced powder used to increase the protein content of milk, state media said.

Zhang sold more than 600 tons of the powder for 6.83 million yuan (998,000 dollars) to dairy producers, the agency quoted prosecutors as saying.

The court also heard charges that Zhang Yanzhang had bought and sold 230 tons of the powder to milk dealers in Shijiazhuang and three other cities in Hebei.

Some of the dealers added the powder to raw milk that was then sold to the Shijiazhuang-based Sanlu group, one of China's major dairy produce retailers.

Local courts in three counties near Shijiazhuang also tried four more milk dealers who had added melamine-laced powder to fresh milk sold to Sanlu, the agency said.

The four courts did not announce when they will make their verdicts public, it said.

Hebei police have arrested at least a dozen others linked to contaminated milk powder produced by Sanlu, which was declared bankrupt earlier this week with debts of 1.1 billion yuan (161 million dollars) after ceasing production in September.

Baby milk powder contaminated with melamine led to the death of at least six infants in China earlier this year and is believed to have sickened more than 294,000 others, according to the health ministry.

Most of those treated had consumed baby milk powder made by Sanlu.

The Shijiazhuang court is scheduled to try Tian Wenhua, the former general manager of Sanlu, next week.

Government officials said Sanlu knew about the contamination of milk powder with melamine since March but didn't order a national recall of the powder until September.

Health inspectors also found illegal levels of melamine in some liquid milk and yoghurt sold by three other leading dairy producers - Yili, Mengniu and Bright Dairy.

Melamine is used as a binding agent and coating for particle, fibre and laminated board in furniture. It is also used to make fertilizer. (dpa)