By Quentin Sommerville BBC correspondent, Shanghai

The fake Viagra was sold over the internet

Eleven Chinese citizens and an American man have been arrested in a counterfeit medicine scheme that spanned 11 countries.

It involved around $4m-worth of fake drugs, officials of both countries have said.

But it is a rare success in China's attempts to safeguard intellectual property rights.

The arrested men are accused of manufacturing fake versions of well-known drugs including Viagra and the cholesterol-reducing Lipitor.

The drugs were made in China, sold on the internet and delivered by mail to customers in Britain, America and Israel.

It was a tip-off from the pharmaceutical company, Pfizer, that led to the investigation.

Both US and Chinese officials have made much of the arrests.

China has promised to put the counterfeiters out of business and respect intellectual property rights in advance of the 2008 Beijing Olympics.

But still the country is awash with counterfeit goods. DVDs, designer handbags and even well-known food brands are pirated here in enormous quantities.