One in three human trafficking victims is a child, most victims are female, and traffickers operate with wide impunity, the United Nations said Monday in a report on modern-day slavery.

The 2014 Global Report on Trafficking in Persons, produced by the United Nations Office on Drugs and Crime, also found that the proportion of children among victims appeared to be rising. Its first report, in 2012, said the proportion had been closer to one in four.

In some regions, like Africa and the Middle East, the new report said, two out of three victims are children.

The office, based in Vienna, was authorized by the General Assembly in 2010 to collect information and publish a global report on trafficking every two years.