The United Nations said on Sunday there could be around 270,000 victims of human trafficking in the European Union and urged greater
efforts to combat the illegal trade.
Authorities in Europe were aware of only a tiny proportion of the victims, said the UN Office on Drugs and Crime (UNODC), estimating there were 30 times more people affected than were known about.
The disclosure came on European Anti-Trafficking Day on Sunday, which aims to draw attention to the plight of victims of the trade who are forced to work illegally after being smuggled across borders.
Antonio Maria Costa, UNODC executive director, highlighted few human traffickers were caught and blamed police for not taking enough action.
Less than one in 100,000 people were convicted for human trafficking in Europe, he said in a statement, adding this was less than "for rare crimes like kidnapping."
"Perhaps police are not finding the traffickers and victims because they are not looking for them," he added.
The majority of victims are women who are forced into prostitution, according to the UNODC.
Men are often forced to work on building sites or farms, and 10 percent of victims are minors, the agency said.