At an indoor pool in Berlin seven migrant boys, all under 15 years old, surrounded underage girls and systematically sexually abused them.

The indoor pool located in Mariendorf, just south of Berlin, is the latest scene of migrant-led sexual abuse of underage girls, reports Die Welt. The seven migrants, six of whom were confirmed to be Syrian, are said to have abused multiple girls in the pool.

According to police, who are now investigating the incident, the migrant youths were between the ages of seven and 14. The group swam behind their victims in the pool and then surrounded them while in the water, groping and touching the underage girls in a sexual manner.

The father of three of the victims explained to German media that his daughters had reported to him and the police that the migrant youths had groped and grabbed her and her sisters’ buttocks and breasts. His daughters, aged nine, 11, and 14, were at the swimming pool with a friend of the eldest daughter who was celebrating her birthday.

After breaking free from the young migrants, the 11-year-old girl was able to inform the lifeguards at the pool. The pool staff immediately called the police who arrived on the scene a short time later.

After being taken into custody by the police, the boys were questioned and then released into the care of their parents. All seven of the migrants are now banned from the pool entirely and police are questioning witnesses.

The case is only the latest in a series of sexual assaults at swimming pools across Germany and neighbouring Austria. Most of the cases have involved migrants targeting underage girls. Often the attackers are adults, though on occasion are underage themselves.

Police in Germany are concerned that the scale of attacks shows little sign of abating, and claimed that there was a large spike over the summer months.

Particularly concerning for many of the victims is whether the attackers will be prosecuted. In one instance, two Afghan migrants who abused a young German boy in a swimming pool changing room were acquitted. The judge stated he found the victim’s story “inconsistent” – despite the testimony of another boy who hid from the migrants and witnessed the abuse.