Chinese officials have confiscated thousands of bags of fake baby formula after 50 babies died from malnutrition.

Chinese Premier Wen Jiabao has called for "severe punishment" of the formula's manufacturers.

Doctors from Anhui province say up to 200 infants were fed the formula and started to waste away. Some died within days of being fed the formula.

Health specialists say the fake formulas contained less than one gram of protein per 100 grams, 1/18th of the standard content. Minerals such as iron and zinc were missing.

With little consumer protection, many products in China are pirated and sold for a fraction of the price of regular products. Anhui is considered a poor region in central China, where farmers make about $325 a year.

Officials say the products had fake seals of approval and letters they sent to manufacturers were returned because the addresses were invented.

Inspectors have seized at least three dozen different brands of fake formula.