Fifteen women were rescued today as police raided a series of brothels in a major crackdown on human trafficking in the North.
The women, from European Union countries, were believed to have been forced into working as prostitutes in Belfast.
Police detained three people during UK-wide property searches and they will be questioned in the North.
Detective Chief Superintendent Roy McComb, head of the PSNI organised crime branch, said: “This is modern-day slavery where human beings are treated like commodities by sophisticated organised crime gangs who are making substantial criminal profits from the sex trade.
“These gangs have no thought for the health and well-being of their victims. They see them simply as instruments to help them generate cash.”
A total of 15 properties were searched across the UK.
Mr McComb added: “Human trafficking and prostitution is no longer gender specific. Men and women are being tricked or forced into prostitution in major towns and cities.
“They are being robbed of their liberty, stripped of their dignity, and suffer intolerable conditions as unwilling emblems of the sex trade.”
Patrick Yu, executive director of the Northern Ireland Council for Ethnic Minorities, said the discovery was welcome but warned the women needed protection.
“In most cases they don’t want to testify (against their captors) because their family may be in danger at home,” he said.
He added they were often simply deported without further ado.
Patricia Lyness, a project manager at the Women’s Aid Federation, said the authorities had made an effort to improve their handling of the trafficked women.
“I think really both the Department of Justice, who have responsibility for it, and the PSNI are working very hard to provide support to the victims,” she said.
SDLP Assembly member Dolores Kelly said she was shocked at the scale of the operation.
“It is a most foul activity in terms of preying on the most vulnerable people. It is welcome news but it is worrying that it may be just the tip of the iceberg,” she said.
Alliance Party MLA Anna Lo said the victims should be properly taken care of.
“This is a sickening crime carried out by callous individuals who see no moral problem in buying and selling human beings,” she said.
“These people must be stopped before more victims are forced into what amounts to 21st century slavery.”