Police in Athens yesterday arrested three Chinese suspected of participation in a crime ring that smuggled thousands of illegal immigrants from China into Western Europe.

The gang, which Attica Criminal Investigation Department (CID) chief Stefanos Skotis described as “one of the toughest criminal organizations in Europe,” allegedly forced the migrants to provide slave labor in order to cover the costs of their clandestine transportation, often torturing those who did not pay up.

The predawn arrests were part of a joint operation that followed a three-year investigation. It was launched simultaneously in Greece and Italy, where six more suspects were taken into custody.

The three people arrested in Athens — two women and a man — owned shops in the city which police believe were used as fronts for the gang’s activities.

Yesterday’s crackdown came two years after a similar operation in Athens, in which 10 Chinese were arrested. They were charged with smuggling into the country Chinese workers, who were held against their will and tortured to force their families in China to send money the gang wanted to take the migrants to Italy.

Three of the Chinese arrested in 2003 were convicted for 11 to 25 years. Another three received five-year sentences, and four were acquitted. In March 2004, police in Athens arrested another member of the gang and freed five Chinese illegal migrants the smuggler had been holding captive.

Italian authorities sent six international arrest warrants to Greece, which prompted the detention of the three suspects yesterday. A fourth person mentioned in the warrants is already in prison for smuggling migrants. Another has been deported, and police are looking for the sixth.

The gang transported young Chinese from poor parts of the country to Western Europe through Russia, Jordan, Turkey, Greece and Italy. The migrants were not asked to pay in advance for the service, on the understanding that they would each give the gang 7,000-15,000 euros upon arrival in Western Europe.

In Italy, police yesterday discovered a makeshift hospital where gangsters treated migrants who had been injured during torture sessions.