A woman and two men have been charged with human trafficking following raids at seven suspected brothels in Belfast.
The woman, 21, and the two men, aged 33 and 46, face charges of trafficking for sexual exploitation, controlling prostitution, brothel keeping and money laundering.
Another woman, 22, was charged with controlling prostitution.
All four are expected to appear before Belfast Magistrates' Court on Monday.
The raids were part of the UK-wide operation Operation Apsis.
Police said the objective was "to recover victims, both UK and foreign nationals," who have been trafficked for sexual exploitation.
In all, officers searched 16 properties across the country.
Police said 12 women and three men who, they believe, were being forced to work as prostitutes, were rescued.
They would not say how many of them were from Northern Ireland.