Madrid (CNN) -- A gang that smuggled Chinese citizens into the United States and Europe, sometimes forcing them to work as prostitutes, has been busted with 75 arrests in Spain and France, authorities announced Saturday.
The trafficking ring was based in -- and directed from -- China, but its two suspected leaders in Europe were arrested in the operation, in Barcelona, Spanish national police said in a statement.
Besides the two main suspects, Spanish police arrested 49 others carrying forged passports at the airports in Barcelona, Madrid, Palma de Mallorca and five other cities. In France, there were 24 arrests.
The smugglers charged 40,000 to 50,000 euros ($53,000 to $66,000) to transport Chinese citizens, assigned with false identities, to the United States, Spain, France, Greece, Italy, Britain, Ireland and Turkey, the statement said. Spain was the next-to-last stop for many before they went to the preferred locations of the United States and Britain, the statement said.
The arrests were made last June and the case, at Spain's National Court, has been under seal until now, a national police spokesman told CNN on Saturday.
All of the suspects are Chinese, or from elsewhere in Asia. All have had initial court appearances and have been ordered to remain in prison while the investigation continues or have been released by the judge, with conditions, said the spokesman, who by custom is not identified.
The suspects include those who allegedly formed part of the smuggling ring and also those who paid for the forged documents, the spokesman said.
Police seized 81 forged passports, ostensibly from Japan, Malaysia, Hong Kong, Singapore, South Korea and Taiwan -- but all made in China, they said. Investigators also found three laptop computers, printers and 22 rubber stamps used to forge documents at homes they said the gang used in Barcelona, police said.
The probe began two years ago. Investigators said the trafficking ring was intricately structured, divided into independent and virtually isolated cells to avoid detection, police said.
The smugglers used their own set of trustworthy travel enforcers, well-versed in the airports and cities where the Chinese were taken. They kept the travelers under control, sometimes trying to pass them off unnoticed among groups of legitimate Chinese tourists.
The ring was quick to react to security changes on the ground at a given airport, swiftly changing to another destination where it would be easier to have their people slip past security controls, the statement said.
Once a delivery of smuggled Chinese citizens had been completed, the travel enforcers would return to their bases in China and Malaysia to await further instructions, and to avoid detection by Western police forces, police said.
Spanish police have been active in recent years in fighting human trafficking rings that lured citizens from Asia, Africa or Eastern Europe to Spain. The victims are often promised a better life, but then subjected to harsh forced labor conditions in clandestine factories or forced them into prostitution.