In 2013-2014, 15,846 people, including 2,500 children, were registered as victims of human trafficking in the European Union, according to combined data from EU governments and Europol, the European Commission said in the paper.

However, EU Migration and Home Affairs Commissioner Dimitris Avramopoulos stressed that the actual numbers are probably much higher because many victims may be afraid or unable to contact the authorities.

“It’s morally and legally unacceptable that in today’s Europe there are women, men, boys and girls who are bought, sold and exploited like commodities. It’s our personal, collective and legal duty to put an end to this,” Avramopoulos said as he presented the Report on progress made in the fight against trafficking in human beings in Brussels.

The phenomenon of human trafficking, especially of children, “has been exacerbated by the ongoing migration crisis,” the report states.

Over half of those trafficked were young women who were brought to the European Union for sexual exploitation, the paper said.

They are deceived into making the journey by the promise of a better job or marriage in Europe, and then turned into slaves.

Most of the females came from nations within the EU such as Romania, Bulgaria, Hungary, Poland, and the Netherlands.

There were also victims from countries outside the block, including Albania, Nigeria, China, Vietnam, and Morocco.

The rest of those subject to human trafficking are forced into involuntary labor, mainly in agriculture or domestic servitude.

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Many were also forced to beg or steal, had their organs harvested, or their children sold for illegal adoptions, the report said.

“Child trafficking is increasing very sharply, with 2500 registered victims. This is a very worrying trend, particularly with the migration wave, we’ve seen an increase of victims arriving from Libya,” Myria Vassiliadou, the EU’s anti-trafficking coordinator, stressed.

Europol had warned earlier that the whereabouts of at least 10,000 children and underage migrants who arrived in the EU unaccompanied in 2014-2015 are currently unknown to authorities, adding that there is a high probability that they have fallen victim to traffickers.

“Organized crime groups choose to traffic children as they are easy to recruit and quick to replace, they can also keep under their control child victims relatively cheaply and discreetly,” the report said.

Trafficked children range in age from six months to 10 years and are sold for sums between €4,000 and €8,000.

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According to Europol, the migrant smuggling business brought criminals between $5 and $6 billion in 2015.

While presenting the report, EU officials also urged national governments to put extra effort into breaking up human trafficking rings and attracted attention to “worryingly low convictions” for human traffickers within the block.