More than 11,000 people are listed as missing in Germany, including some 7,000 who are under the age of 18, federal law enforcement officials said.

Around half of the missing minors are unaccompanied refugees. As of Oct. 1, around 3,500 of them were unaccounted for, including 902 under 13 years old. But these figures could "only serve as an approximation," a spokeswoman for the Federal Criminal Police Office (BKA) told dpa.

Several factors make it difficult to arrive at the exact number, including refugees who are listed multiple times due to different spellings of their name. The list includes those missing for just a few days and others who haven't been seen in decades. "Experience has shown that about 50 per cent of missing cases are closed within the first week," the BKA spokeswoman said.

Armin Gartelmann, head of the missing persons unit at the Bremen police department, said, "There are people who go to hospital for a week and don't tell anyone. Others go on vacation and don't tell anyone."

The problem of missing children and adolescents has long been known by German authorities. It is always pointed out by the authorities that, in some cases, multiple registrations could be the cause, or the unaccompanied refugees might have tried to move to other European countries to find their relatives. As safe information is lacking, however, it is equally possible that some of the children and young people were victims of criminals.

In July 2017, nearly 6,000 children were listed as missing in Germany. According to statistics BKA, 945 children aged 13 and under, and 5,502 children between the ages of 14 and 17 have already been registered as missing. The German children's fund office (Deutsche Kinderhilfswerk) has urged the German government to take concrete steps in searching for refugee children as they face the danger of falling into the hands of criminal organizations, and that most of the refugee children who went to Europe did not have any relatives there.