Gao Qiang, an official in China's Health Ministry who disclosed the detentions, said the contaminated Sanlu brand powdered milk had not been sold outside the mainland and Taiwan, Xinhua reported. Production of the formula has been halted and stores were pulling it from their shelves, the state-run news agency said.

"None of the milk powder was exported to other countries or regions," Gao said. "Only a fraction of the milk powder was sold to Taiwan for food processing."

The tainted formula is being blamed for at least 432 cases of kidney stones in babies in seven Chinese provinces. One child reportedly died of the ailment but it wasn't clear it had consumed the same brand of formula.

Sanlu Group said it had found some of its baby milk powder products were contaminated by tripolycyanamide, Xinhua said.

The government issued a statement Saturday evening saying the formula had been deliberately contaminated with melamine to increase the protein percentage in raw milk or milk powder, Xinhua said.

The State Council established a special investigatory group to look into the incident.