Spanish police have busted a Chinese drug trafficking and prostitution ring suspected of having operated up to 37 brothels in Barcelona, officials said on Wednesday.

Some 33 people were taken into custody as a result of the operation last week in what police said was one of the biggest coups against Asian mafia on Spanish soil, police said in a statement.

Some 30 women who had been forced to work in the brothels have been remanded to specialised care associations, they said.

The women were forced to provide unprotected sex in flats throughout Barcelona, sometimes to as many as eight clients within a single hour. Several of them were infected with HIV and one had committed suicide.

The ring ran up to 37 brothels with some 100 women from abroad who arrived in Barcelona owing up to 20,000 euros ($26,700) to the network for having been smuggled into the country.

Police also seized 2,500 ecstasy pellets during the operation.