Six eastern European women have been rescued after detectives swooped on a human trafficking ring which is part of a major Europe-wide vice operation.
Four suspects - three men and a woman - were arrested and were being questioned by the PSNI's Organised Crime Branch last night.
Eye-witnesses described how a number of police Land Rovers and unmarked police cars swept into King Street in Belfast city centre yesterday around 10am.
In dramatic scenes they raided a large apartment block adjacent to the Ibis hotel and arrested two men, aged 22 and 29.
One witness, who did not wish to be named, said the apartments were known to be a base for prostitutes, with clients visiting at all hours.
Two of the women, both in their 20s, were rescued yesterday from the King Street apartment block and a property in nearby College Place North.
The other four women were rescued over recent weeks during the three-month long PSNI investigation.
The rescued women were taken to the CARE suite at Garnerville where they were given specialist support and offered services provided by the UK Human Trafficking Centre.
A 24-year-old man and a 22-year-old woman were also arrested in Cavendish Street, off the Falls Road in west Belfast. One of the suspects is from Northern Ireland, the other three arrested are eastern European.
Human trafficking is on the rise in Northern Ireland with yesterday's rescues bringing to 23 the number of people saved from human trafficking since the start of April.
This is equivalent to the total rescued for the whole of the previous year.
The officer leading the investigation, Detective Inspector Douglas Grant, said: "We have been investigating a trafficking and prostitution ring stretching across Europe for the past three months.
"Police have an ongoing commitment to rescue victims of human trafficking, who in this case we believe were being used for the vice trade. And we have an equally strong commitment to dismantle the organised crime gangs involved.
"Today's arrest and rescue operation is the latest stage in this ongoing, proactive investigation. Our inquiries will continue over the coming weeks and will involve other law enforcement agencies across Europe."
A total of 23 people have been rescued from human traffickers in Northern Ireland since April 1. Justice Minister David Ford launched the Blue Blindfold campaign, aimed at raising awareness of the issue. Women from as far away as India have been trafficked to Northern Ireland. Men and boys have also been trafficked.