Three men have been arrested in raids targeting the suspected trafficking of women from Eastern Europe for sex work.
Northumbria Police raided four properties in Newcastle earlier as part of an investigation into modern day slavery.
Four "vulnerable" women were taken into police protection, a spokesman said.
The three men were arrested on suspicion of modern day slavery and trafficking offences are being held in police custody.
Northumbria Police believe the women, most of whom are from Romania, were being brought to the UK and kept in cramped houses while being forced into sex work.