The European Union's planned migration policy should include measures to stop thousands of unaccompanied child migrants from disappearing, the UN Children's Fund (UNICEF) demanded Friday in Geneva.
The number of underage asylum seekers surged to a record 96,500 last year in European countries, according to the UN agency.
The European police body Europol estimates that one in nine of such children go missing or are unaccounted for.
UNICEF noted that the number is likely far higher and warned that children who disappear are at serious risk of being abused, trafficked or exploited.
While young asylum seekers currently have to wait up to 11 months to be transferred to a European country that accept them, this period should be shortened to three months at most, UNICEF said.
In addition, authorities should appoint legal guardians for such children immediately, and they should speed up family reunification procedures, the UN agency added.
"Unaccompanied children are falling between the cracks," said Marie-Pierre Poirier, UNICEF's coordinator for the European migration crisis.
Many children run away from refugee reception centres to join their families instead of waiting, she said.
Others leave because they have not had a full hearing of their case, or because they did not have adequate legal counsel, Poirier added.
UNICEF's appeal came in reaction to new proposals that the EU executive body issued Wednesday to help the bloc cope better with flows of migrants and asylum seekers.
Among its proposals, the European Commission plans to strengthen the rights of unaccompanied minors, and to speed up asylum procedures in general.
Among the unaccompanied minors that sought protection in Europe last year, 88,300 were registered in EU countries.
Half of them came from Afghanistan last year, while the second biggest group came from Syria, according to according to the EU statistics agency Eurostat.