Dutch and Romanian police have arrested 13 people in a joint investigation into human trafficking and the forced prostitution of Romanian women, mainly in and around Amsterdam, officials said on Monday.

The suspects, all Romanian nationals aged between 20 and 43, were detained during a coordinated campaign on July 1.

Six arrests were made in the Netherlands and seven in Romania. Four of those detained in Romania have since been extradited to the Netherlands under a European arrest warrant.

The investigation centres on a suspected criminal network that approached vulnerable women through social media and began what appeared to be romantic relationships.

The women, aged between 21 and 37, were persuaded to enter prostitution under the illusion they were being offered love, safety and financial stability.

Police said the suspects made the women emotionally and financially dependent, and in some cases used psychological pressure or violence when the victims wanted to stop.

The group is thought to have been active for several years. At least 10 women have been identified as victims, but Amsterdam police said more may come forward.

During house searches in both countries, police seized vehicles, cash and digital devices. The proceeds from the exploitation were allegedly laundered and invested in luxury goods and property in Romania.

Eight suspects remain in custody in the Netherlands. The investigation is ongoing and further arrests have not been ruled out.