The police said the arrests took place following a request for cooperation from the Taiwanese National Police, which "acknowledged that several citizens of that territory [Taiwan] were victims of human trafficking in Portugal, in a situation of kidnapping, coercion and slavery".

The National Counter-Terrorism Unit (UNCT) located an isolated house in the Cascais area where it found and rescued 17 citizens deprived of freedom, documents and unable to maintain contact with the outside world.

In the course of the operation, dozens of telephone and telecommunications equipment, computer equipment, documents and money were seized.

One man was sent for judicial interrogation and has to go to the police three times a week.

"In view of the continuation of the criminal investigation efforts by the Taiwanese authorities to arrest the main perpetrators of this illegal activity, the police action had not been made public', it added.

The police said that "several people have already been arrested and more than a dozen others involved in this criminal scheme in that country have been identified".

In the note, the Portuguese police recalled that this was the first time in Europe that the police authorities managed to dismantle, in full operation, an organised group of this type.