Europol, the European Union’s criminal intelligence agency, reports that at least 10,000 refugee children have gone missing since arriving in Europe. Brian Donald, Europol’s chief of staff, worries that an E.U.-wide “criminal infrastructure” of trafficking syndicates is targeting unaccompanied minors, the Guardian reports.

“It’s not unreasonable to say that we’re looking at 10,000-plus children. Not all of them will be criminally exploited; some might have been passed on to family members. We just don’t know where they are, what they’re doing or whom they are with,” Donald said.

Five thousand children have reportedly disappeared in Italy alone, and another 1,000 in Sweden. From the Guardian:

The plight of unaccompanied child refugees has emerged as one of the most pressing issues in the migrant crisis. Last week it was announced that Britain would accept more unaccompanied minors from Syria and other conflict zones. According to Save the Children, an estimated 26,000 unaccompanied children entered Europe last year. Europol, which has a 900-strong force of intelligence analysts and police liaison officers, believes 27% of the million arrivals in Europe last year were minors.

“Whether they are registered or not, we’re talking about 270,000 children. Not all of those are unaccompanied, but we also have evidence that a large proportion might be,” said Donald, indicating that the 10,000 figure is likely to be a conservative estimate of the actual number of unaccompanied minors who have disappeared since entering Europe.

In October, officials in the southern Swedish port town of Trelleborg reported that 1,000 unaccompanied children had gone missing in the previous month. A subsequent report found that there is “very little information about what happens after the disappearance.”

Europol has received evidence that some of children are sexually exploited, as organized gangs of smugglers collaborate with human-trafficking gangs. “An entire [criminal] infrastructure has developed over the past 18 months around exploiting the migrant flow,” Donald said.

Photo via AP Images. Contact the author of this post: brendan.oconnor@gawker.com.