Madrid  - Spanish police have smashed a Nigerian criminal ring which may have swindled about 170 million euros (238 million dollars) from thousands of US and European Union citizens, police said Thursday.

Police detained 87 people in the Madrid region, acting in coordination with the US Federal Bureau of Investigation (FBI).

The suspects were believed to have sent letters from Spain, telling the addressees they had won a Spanish lottery jackpot and needed to pay an initial fee of 900 euros to cover taxes and other costs.

The victims included a US Anglican bishop who lost 18,000 euros.

Police searched 39 addresses, seizing more than 60,000 letters ready to send. The fraud was profitable even if only one in 1,000 addressees fell for it.

Police launched the investigation in May 2007 on discovering the dispatch of large amounts of identical letters from Madrid. The swindlers found the addresses of their victims in data bases of easy access on the internet, police said.

Police sources described the scam as a new version of the "Nigerian letters," in which people pretending to be representatives of the Nigerian government or institutions asked for help in getting a large amount of money out of the country.(dpa)