Almost 9,000 unaccompanied refugee children are officially missing in Germany, according to new police figures released on Monday.

Authorities have lost trace of 8,991 children registered entering the country as unaccompanied asylum-seekers, including 867 aged 13 or younger, the Bundeskriminalamt (BKA), Germany’s national investigative police agency, said in a report.

Child protection organisations expressed alarm at the disappearances, amid fears some of the children may have been targeted by organised trafficking gangs.

Save the Children said it was “extremely worried” by the newly released German figures, which come just weeks after the charity uncovered evidence of unaccompanied refugee minors being forced to work as prostitutes and child labourers in Italy.