More than 10,000 unaccompanied child refugees have vanished following their arrival in Europe and may have fallen into the hands of organized trafficking gangs, EU’s criminal intelligence agency says. Europol Chief of Staff Brian Donald warned in a Saturday interview with UK-based daily Observer that a sophisticated pan-European “criminal infrastructure” was now targeting refugees, adding that 5,000 of the missing children had disappeared in Italy alone with 1,000 more unaccounted for in Sweden. “It’s not unreasonable to say that we’re looking at 10,000-plus children,” Donald stated. “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.” He said the minors went missing after registering with state authorities, noting that the discovery came to light in the first attempt by European law enforcement agencies to keep track of one of the most disturbing aspects of the continent’s refugee crisis. “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,” Donald emphasized, suggesting that the figure would likely prove to be a conservative estimate and the actual number may be even higher. According to UK-based NGO Save the Children, an estimated 26,000 unaccompanied children entered Europe in 2015. This is while Europol, which has a 900-strong force of intelligence analysts and police liaison officers, believes 27 percent of the nearly one million asylum seekers that arrived in Europe last year were minors. According to the British daily, officials in southern Swedish city of Trelleborg revealed that some 1,000 unaccompanied refugee children that had entered the port city over the previous month had disappeared. A separate report released Tuesday in Sweden further warned that many unaccompanied refugees had gone missing and that there was “very little information about what happens after the disappearance.” In the UK, the daily adds, the number of child refugees that vanish soon after arriving as asylum seekers has doubled over the past year, raising concerns that they are also being targeted by criminal gangs.