Chinese police have detained five wholesalers of fake milk powder after malnutrition caused the deaths of 13 babies and sparked a national outcry at the latest counterfeit product sold to consumers, state media said on Thursday.

Police were trying to identify the manufacturer of the substandard infant formula peddled in rural areas around Fuyang in the eastern province of Anhui and authorities were raiding local markets, the reports said.

“Two wholesale dealers…have revealed the places where they had bought the milk powder,” the official Xinhua news agency said.

Firms accused of selling what has been dubbed “killer milk powder” have professed their innocence to state media, saying they were being framed by competitors.

Counterfeit goods are common in China in a rush to get rich quick, and Vice Premier Wu Yi vowed on Wednesday in Washington to crack down on faking of billions of dollars of U.S. goods and to lower the legal threshold for criminal penalties.

Most of the infants were just three to five months old and have been called “big headed babies” because their bodies wasted away while their heads swelled from malnutrition after being fed the cheap fake formula.

Most were born in the dirt-poor agricultural province of Anhui, around 190 miles inland from Shanghai.

Parents of the sick babies told state media they bought the cheapest milk powder available, costing just 10 yuan ($1.20) for half a kg, compared with 60 yuan for more expensive brands.

Investigators said they had unearthed dozens of knock-off milk powder brands in many provinces, complicating efforts to eliminate the business.

Investigators had inspected 205 types of milk powder in the Fuyang area of Anhui and found 55 brands were sub-standard - short of protein and other nutrients, China Central Television said.

One raid on milk powder markets in Fuyang had uncovered 42 cases of substandard powder, Xinhua said.

“The local government is working hard to find the source of inferior milk powder,” Xinhua said.

The powder had been traced to 141 factories in the provinces of Heilongjiang, Zhejiang, Shandong, Hebei, Hubei and Jiangxi in Beijing and Shanghai municipalities and in the Inner Mongolia Autonomous Region, Xinhua said.

Premier Wen Jiabao ordered a cabinet probe into the deaths, details of which have been splashed on television and in newspapers.

Investigators found 171 infants suffering from malnutrition after being fed on the formula sold in Fuyang. Two babies were still being treated in hospital.

The Fuyang government would offer free medical treatment to the malnourished babies and 10,000 yuan ($1,200) in compensation to families of the victims, state television said.