Belgian police detained as many as 25 people on suspicion of trafficking women from China for prostitution, the federal prosecutor's office said on Tuesday.

Belgian police conducted a series of raids across 26 addresses in Belgium, as well as in the Spanish cities of Alicante and Barcelona. 

One suspect was detained in Spain as well, officials said, with Belgian officials asking for the suspect to be extradited to Belgium.

Three of those detained are Belgians, while the rest are Chinese nationals. Belgian police also said they discovered 20 alleged victims of trafficking, all Chinese, during the raids across Belgian cities of Antwerp, Charleroi, Louvain, Neufchateau and Brussels.

What do we know about the alleged sex trafficking ring?

Prosecutors said there were aware about the increasing presence of Chinese sex workers in Belgium.

They said the criminal organization they were probing allegedly recruited women in China and had them travel to Europe, where they were "sexually exploited, mostly in private prostitution." The women were forced to give up most of their earnings as well, prosecutors said.

The alleged members of the prostitution ring used online websites to offer sex, while clients booked appointments with the women there. They booked online rentals like hotels or vacation homes for sex trafficking.

The women were also "often moved around Europe" and many of the women were without valid European residency papers, which "increased their dependency" on the organization, the office said.

The criminal organization earned large sums of money and transferred it abroad through legal and illegal channels, according to the office.

Some of the victims found by the police on Tuesday were sheltered in a specialized reception centers, prosecutors said.

The European Union's Agency for Criminal Justice Cooperation, or Eurojust, and the European Union's law enforcement agency, or Europol, were part of the investigation as well.

rm/rt (Reuters, AFP, AP)