SHANGHAI: China's health regulator said on Monday all domestic medical institutions must cooperate with authorities and not use the valsartan blood and heart drug made by Zhejiang Huahai Pharmaceutical that could pose cancer risks.

The bulk manufacturer of the drug said earlier this month that it was recalling the valsartan drug sold in the United States after the European Medicines Agency found that it was tainted with an impurity linked to cancer.

In a notice posted on its website, China's National Health and Family Planning Commission said the recalled drug, commonly used to treat patients with high blood pressure, should not be used for the diagnosis and treatment of diseases.

European regulators have said that the problem likely dates to changes introduced into manufacturing processes at the company in 2012, suggesting that many patients could have been exposed to cancer risk.

The drug has already been withdrawn in the United States and Europe and China's drug regulator said on Sunday that Huahai had completed the withdrawal in China of the raw materials used to produce the drug.

The Chinese health regulator also said that there were six local companies that used valsartan made by Huahai. Five of these companies had products on the market and have since issued recalls, it added.

The sixth firm, the Hunan branch of Zhuzhou Qianjin Pharmaceutical, had not yet shipped out its products, the regulator said. The company said in a statement that it returned Huahai's valsartan earlier this month and that none of its products were affected by the product recalls.

Huahai said on Monday that its other products did not contain the impurity known as NDMA, which is classified as a probable human carcinogen, and that it would continue to improve its systems to prevent similar incidents from happening.