China's food and drug safety watchdog revoked the production licenses of two gel capsule producers in the eastern province of Zhejiang amid a scandal involving the manufacture of contaminated medicine capsules, according to an official statement issued Thursday.

The State Food and Drug Administration (SFDA) said in the statement that it ordered the Zhejiang provincial drug authority to revoke the licenses of the Huaxing and Zhuokang plants for "grave violations of laws and regulations," without specifying their wrongdoings.

Moreover, those from the two plants who are suspected of criminal offenses will face criminal charges, the statement said.

Investigations into other relevant enterprises are underway, according to the statement. Once the offenses are confirmed, violators will be handed out harsh punishments.

The SFDA promised to strengthen monitoring and firmly crack down on such illegal conduct and prevent industrial gelatin from being used in the production of drug capsules.

On Sunday, an investigative report from China Central Television revealed that several companies in Xinchang, a major pharmaceutical production hub in Zhejiang, manufactured drug capsules with industrial gelatin, which contains a greater amount of chromium than edible gelatin.

Chromium can be toxic and carcinogenic if ingested in excessive amounts.

The report showed that the industrial gelatine used to manufacture the capsules was made from scraps of leather material.

The SFDA issued an emergency notice late Sunday, calling for a halt to the sale and consumption of a list of drugs that may have been packed into the contaminated capsules.

The SFDA has also instructed its local bureaus to investigate the cases and examine the drugs mentioned in the report.