The number of unaccompanied refugee minors who became wards of the German state in 2015 climbed to 42,300, an increase of 263 percent over the previous year, Germany's statistics office Destatis said on Tuesday.

The office, which has been keeping count of child refugees since 1995, said the number of those taken into state care corresponded with the number of arrivals.

Only 53 percent of refugee minors who arrived in 2015 had applied for asylum, it said, blaming the low rate on bottlenecks among authorities in charge of registering asylum seekers.

It said in a statement that about 91 percent of the unaccompanied children and teenagers were male, with just 3,600 girls entering Germany without parents or carers.

Young migrants in danger

The federal migration agency, BAMF, says the numbers are in fact lower, as many refugee minors are registered several times. It also noted a significant decrease in the number of unaccompanied minors since November.

Aid groups have frequently warned of the dangers faced by young unaccompanied migrants,including those posed by organized crime rings who exploit them for the purposes of prostitution, begging, pornography or other criminal activities.

Many of the young refugees are also suffering from problems related to their experiences of conflict in their countries of origin.

Germany saw an unprecedented influx of migrants and refugees in 2015, with more than 1 million people registering for asylum. Most of them came from Syria, Afghanistan and Iraq, which have all experienced current or recent armed conflicts.

tj/kms (dpa, AP)