"As large numbers of refugees and migrants arrive, children among them are routinely left in conditions that would be deemed unacceptable for native-born children", UNICEF said."Some children avoid authorities for fear of detention, living on the streets under abysmal conditions and sometimes selling sex or resorting to petty crime as they save up to pay smugglers to facilitate their onward journeys".
In March, Italy's Parliament approved a law setting out comprehensive standards of care for unaccompanied migrant children who arrive in Italy by sea.
Hundreds of thousands of unaccompanied children attempted to cross borders to seek safety over a two-year period.
Those who survived the journeys recounted harrowing stories of abuse along the way, including a 17-year-old girl from Nigeria who told officials that she was raped in Libya by a man who had promised her passage to Europe. The report shows that an increasing number of these children are taking highly risky routes, often at the mercy of smugglers and traffickers, to reach their destinations, clearly justifying the need for a global protection system to keep them safe from exploitation, abuse and death.
When they can't find opportunities to move legally, children sometimes have to resort to risky routes and engage smugglers to help them cross borders. When describing the smuggler turned trafficker who offered to help her, she said, "Everything (he) said, that we would be treated well, and that we would be safe, it was all wrong". Despite promising to keep her safe, she ended up stuck in Libya for more than three months.
Almost two million people from a population of 12 million have fled South Sudan in the growing crisis - one million of those fleeing are children. The report added that 170,000 unaccompanied children applied for asylum in Europe from 2015-16.More news: Germany's Schulz sees 'rocky road' to election after key state defeat
Among a raft of alarming statistics, the report finds that children account for approximately 28 per cent of trafficking victims globally.
Sub-Saharan Africa and Central America and the Caribbean have the highest share of children among detected trafficking victims at 64 and 62 per cent respectively.
The boom in global migration has been matched by a massive increase in smugglers, according to Europol.
With the G7 meeting in Italy next week, UNICEF is calling on governments to address the problem and adopt their six-point plan.
Many of the Unicef report's findings echo a Harvard University study on migrant children in Greece (pdf), published by Harvard University earlier this year, which warned that "children gravitate towards risky and illegal activities to pay smugglers, including theft, drug dealing and transactional sex".