Industry body IFPI has partnered with police forces in four European countries to tackle a suspected piracy ring which had generated more than €19 million ($26.3 million) in illegal sales.

More than 100 police officers were involved in the operation, which targeted the European manufacturers and distributors of unlicensed CD and DVD "Masterbox" sets.

According to a statement from the IFPI, releases in the "Masterbox" series contained a range of unlicensed music, film and TV content, including pre-release titles.

IFPI identified Black Eyed Peas, Michael Jackson, Green Day and Robbie Williams among the artists included in the "Masterbox" series, which ran to more than 50 editions, had a street value of approx €40 ($55) and were predominantly sold in the Netherlands.

An estimated 450,000 copies of the series had been sold to date over the past four years, according to IFPI, generating sales revenue of more than €19 million ($26.3 million). The box sets were largely sold in markets, workplaces, pubs and restaurants throughout Holland.

Police raids took place last week on eight business premises and five homes across Belgium, Bulgaria, the Netherlands and Spain. Ten days ago, police from Bulgaria's Cyber Crime Unit also raided manufacturing plants in Sofia and Plovdiv suspected of producing the illegal box sets, although the news was kept secret so as not to damage the overall operation.

Officers from the Dutch fiscal police (FIOD-ECD) arrested three individuals in the Netherlands suspected of selling "Masterbox" releases. They are now helping police with their enquiries; a further suspect was also arrested and held for questioning in Belgium.

In a statement, Jeremy Banks, director, anti-piracy at IFPI, said: "This was a major cross-border anti-piracy action against an operation that we believe was causing very significant losses to the legitimate music industry."