(Adds details on Chinese manufacturer)
LONDON, July 5 (Reuters) - A number of high blood pressure and heart drugs containing an ingredient made in China are being recalled across Europe after an impurity that may cause cancer was found in them, officials said on Thursday.
The European Medicines Agency said the recall followed identification of the impurity in the active substance valsartan manufactured by Zhejiang Huahai Pharmaceuticals, a company in Linhai, China.
Britain's Medicines and Healthcare products Regulatory Agency said the appearance of the impurity - N-nitrosodimethylamine - came after a change in the process for making valsartan at one facility.
Valsartan was originally developed by Novartis and the Swiss company marketed it as Diovan, but it is now off patent and is used in a number of generic medicines.
European regulators said they were working together to investigate the extent of the issue.
Reuters could not immediately reach Zhejiang Huahai Pharmaceuticals for comment outside of regular business hours. (Reporting by Ben Hirschler; Editing by Jan Harvey and Mark Potter)